More than one study has tried to determine the financial price of happiness. Some look at wealth. Others look at income.

One well-publicized study last year put the optimal income for happiness at around $75,000. Rising income, it turns out, produces greater happiness until you get to around $75,000. After that, there are diminishing returns, with more income leading to little or no gain in real happiness. 

This is a fraught question, of course. “Happiness” itself is not easily defined, and money doesn't always guarantee it. And the financial requirements for happiness usually depend on geography, peer groups and other external factors. 

The latest to weigh in on the issue is Skandia International’s Wealth Sentiment Monitor. It found that the global average “happiness income” is around $161,000 for 13 countries surveyed. The United States wasn’t specifically measured. (Read more: Why Millionaires Prefer Dogs) 

But there was a wide range of answers depending on the country. Dubai residents need the most to feel wealthy. They said the needed $276,150 to be happy. Singapore came in second place, with $227,553, followed by Hong Kong, with $197,702. 

The region with the most modest needs for happiness is Europe. Germans only need $85,781 to be happy, placing them lowest on the list. The French need $114,000, while the British need $133,000. 

The survey doesn’t ask about total wealth needed to feel happy. But it does ask about the amount of wealth needed to feel “wealthy.” Globally, the average amount needed to feel wealthy was $1.8 million. 

Singaporeans took the lead on the “wealth” needs, with $2.91 million needed to feel wealthy. Dubai ranked second with $2.5 million, followed by Hong Kong with $2.46 million. (Read more: Where to Live If You Want to Be a Millionaire) 

Surveys show that among Americans, most say they need $1 million or more to feel wealthy.

 All of this shows that wealth and financial happiness is not an absolute number, but is relative to your peers and surroundings. Living in Dubai, with all those oil barons and oligarchs, the needs are higher. In Germany, where wealth is more evenly distributed, the needs are not as high.

 How much wealth or income would you need to feel happy?

Follow Robert Frank on Twitter: @robtfrank

Carolyn Kaster / AP file

A seller works on her hat display at a yard sale. Such sales are one of many ways you can put extra money in your wallet.

So, you're looking to make a little extra cash?

As a parent, any additional income you bring in for your family will definitely be put to good use for, say, a college fund or rainy day savings. You may also need extra bucks for shoes for your toddler, who outgrows hers like she's getting paid to do so.

Because we're probably a little bit too old for lemonade stands, we had to look elsewhere. And guess what? Nowadays, with ubiquitous smartphones and laptops, the easiest ways to earn extra cash are accessible to everyone at the click of a button.

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To help, we hunted down apps, opportunities and projects and chose nine "extracurriculars" that are particularly flexible in nature, so you can earn some cash while the kids are at school ... or maybe even bring them with you.

Download apps

Apps aren't only fun — they're income!

Easyshift is an app that lets you moonlight as a "mystery shopper." When you go on your regular errands, you complete tasks for retailers' research departments like taking pictures or answering a few questions, and you get paid ($2–$4 per task) for the privilege.

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Other apps for extra cash include WeReward and Field Agent.

Multitask your errands

Have you heard of TaskRabbit? It's a website (and app) that lets you outsource chores to willing parties. If you're one of those willing parties, you can earn some extra cash doing anything from picking up groceries to assembling IKEA cabinets.

Use your car

If you have a reliable car (and some great driving tunes), consider bringing in some extra money from a car-sharing service. Services like ZimRide let you sell seats on trips you're already taking for as much as $25, and services like Relay Rides let you rent out your car at your chosen price for the hour, day or week (and provides free insurance).

And what about parking? If you have it, you can rent that out, too, with Parking Panda.

Baby-sit

Almost everyone has dabbled in baby-sitting at some point, but the job only becomes more lucrative as you grow older and are able to offer more skills, like driving, cooking or CPR certification.

Websites like SitterCity or Care.com are great resources for matching sitters with families.

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Charging $12–$15 per hour is pretty standard, but to figure out how much is appropriate for your age and experience, use SitterCity's Babysitter's Rate Calculator.

Spread your availability by speaking with your child's teachers, any friends who work in your community and with real estate brokers, who may work with families with small children who are new to town. If possible, you may even consider an arrangement where you can watch children at your house; it's a built-in play date for your own kid!

(Prefer watching four-legged cuties rather than two? Petsitting.com has you covered.)

Sell your clothes

Another way to finance your habit might be cleaning out your closet — and your child's. It's doubly beneficial: You can clear clutter and make some cash at the same time.

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Start by choosing high quality pieces from the current season without any visible wear and tear. Make sure they're clean and folded, then bring them into your local consignment store.

If it's easier, take well-lit pictures of the pieces and list them on a site like eBay or Dresm, a site specifically meant to facilitate sales of used clothing.

Tutor

Do you have a masters degree in engineering? Are you a whiz in the kitchen? Do you know the ins and outs of Photoshop?

Any skill someone else wants to learn is an opportunity for you to teach it. Depending on experience and whether or not they join a larger organization, tutors can bring in up to $50 an hour (in cash) teaching out of their own homes, or visiting their students (who could be both children and adults).

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In addition to advertising in your community through standard newspaper ads, Facebook posts and fliers in the library, consider applying to be a tutor on sites like Tutor.com, the Princeton Review and Kaplan.

Take online surveys

If you spend hours surfing the Internet, what's a few extra minutes spent taking a paid online survey?

Websites like Free Paid Surveys or Opinion Place allow you to make money from the comfort of your home. If you're looking for something more interactive, list yourself as available for focus groups by joining FindFocusGroups.com.

Become a style entrepreneur

Style blogs don't have to be a guilty pleasure. Instead, they can be the inspiration for a side job as a "style entrepreneur."

StyleOwner is a free site that lets you create your own store by choosing items from a “Master Closet” of more than 2,000 brands. When your friends — sent that way through your tireless efforts on Facebook, Twitter and emails, no doubt — buy from your store, you earn 10 percent on everything you sell.

Host a yard sale

With the right curatorial skills, yard sales can be a lucrative way to make extra cash. To get the most traffic at your yard sale, advertise on Craigslist and in your town newspaper, and consider coordinating with your neighbors to hold a group sale.

If you're lacking a yard (or half-decent weather), there's also the option of hosting a virtual yard sale: The app Yardsale lets you connect with neighbors and friends without setting up a single folding table.

More Americans are feeling unsure of your financial security but it’s not because of the tough job market.

It's all about those skimpy paychecks.

Stagnant wages for the majority of U.S. households have more consumers curbing their spending and worried about paying down debt, according to a Bankrate.com survey released Wednesday. Inflation-adjusted median family income has declined about 6 percent since it peaked at around $64,000 in 2000.

Bankrate.com’s Financial Security Index looks at job security, savings, debt, net worth and the overall financial situation of consumers; this month the index hit its lowest level since March and experienced its biggest monthly drop since last August. About 1,000 adults were polled via telephone interviews done nationally earlier this month.

Even with the unemployment rate still above 8 percent, surprisingly job security was the least affected part of the index. Most of those polled feel that the jobs outlook was the most improved component this year.

“What's really undermining consumer progress on financial security are stagnant wages,” said Greg McBride, Bankrate’s senior financial analyst. “If incomes aren’t growing it’s difficult for people to make headway on debt and savings.”

Indeed, the U.S. Commerce Department reported in June that consumer spending was unchanged and wages were essentially flat in May. 

Uncertainty over what many have called the “fiscal cliff” is keeping many businesses from hiring, expanding and making big investments, McBride explained. The cliff is referring to $600 billion worth of tax hikes and spending cuts that could automatically kick in January if Congress doesn’t find a compromise. Some economists have warned that it could push the U.S. economy into reverse. 

Bottom line, McBride added, “The economy is still stuck in first gear.”

News flash: Attractive people are happier.

And it all boils down to simple economics, say researchers who get paid to study such things.

If you've been blessed with good looks, you're more likely to be blessed with a bigger bank account, according to new research by economists at The University of Texas at Austin, who've made a career out of examining the interplay of looks, success and money.

"Personal beauty raises happiness," said Daniel Hamermesh, a Texas professor who co-authored the study (.pdf file) with Jason Abrevaya. "The majority of beauty's effect on happiness works through its impact on economic outcomes."

In previous research, Hamermesh has established that beautiful people earn more money and marry better-looking and higher-earning spouses than their plain-Jane counterparts.

The study suggests these indirect economic benefits account for nearly half of the additional happiness that good-looking folks report. Women are more likely than men to report that their happiness is more directly affected by beauty than men.

"For men, almost all the effect is indirect  — through beauty raising their earnings, the kind of spouse they can get, their ease of getting loans, etc." Hamermesh said. "For women, however, those indirect effects account for only half the impact of beauty on happiness. The other half is direct. ... Better-looking women just feel happier."

To reach their conclusions, the economists reviewed five large international studies involving nearly 25,000 participants. To quantify beauty, interviewers rated the participants' attractiveness using set guidelines or evaluated their beauty from pictures.

Instead of looking to traditional institutions or check-cashing stores, millions of low-income Americans are instead turning to their local big-box retailer for their banking needs, according to a report in The Washington Post.

The newspaper reports that Kmart, Best Buy and Wal-Mart are all testing and rolling out in-store banking services ranging from check cashing and money transfers to bill-payment services.

The attraction for these retailers is the $320 billion industry of alternative financial services that the newspaper report says has long operated in the shadow of the formal banking system and under the radar of federal regulators.

Demand for alternative services is expected to grow as strict new rules force banks to charge higher fees for checking accounts, placing them out of reach of many financially strapped households, the Post notes.

The article cites a recent government survey that shows nearly 30 million households either do not have a bank account or scarcely use one. Some 70 percent of families who are considered “unbanked” earn less than $30,000 a year and many say they will never do business at a bank, the paper said.

These households have usually used a hodgepodge of services to manage their money, and retailers have started to realize that those same consumers are shopping in their stores, the Post said (Wal-Mart, for example, has said that one in five of its customers doesn’t have a checking account).