If your smartphone bill is pushing $100 a month, wouldn't it be nice to have a couple of apps that could actually earn you some money?

USA Today has listed some smartphone apps that can bring in real money, for just a little amount of effort.

Survey Supermarket Prices

Gigwalk will pay you from $5 to $20 to take some notes, enter prices, and send some prices at a grocery store near you. Donna Bagara says she earns as much as $125 a week using the app. She is paid through PayPal.

Click here  for the Gigwalk app or go to  www.gigwalk.com  .

Two similar apps, that pay you for scanning items or comparing prices in local stores are Field Agent and Easy Shift.

Click her  e for Field Agent, or go to  www.fieldagent.net  .

Click here  for Easy Shift, or go to  http://easyshiftapp.com.

Do a task, get paid

An app called  TaskRabbit  links up people who need a small job done, and others who are willing to do it for a small fee.

Among the jobs available: buying groceries, putting together IKEA furniture, walking the dog, and many more.  The average chore pays $45, according to the app makers.

Swap your stuff with yard sale

Have a bunch of junk in your garage, but don't want the hassle of holding a garage sale on a Saturday?  Then check out the app called  Yardsale.

It connects people in a community looking to sell or trade items, from baby strollers to old refrigerators. Unlike craigslist, you won't hear from scammers in Africa.

Scan barcodes, earn money

The  CheckPoints  app lets you build up reward points for simply scanning the bar code on groceries.  When you get enough, you redeem points for gift cards.

Target stores have just rolled out a similar program with the app  ShopKick.    Use the price comparison app in a Target store, and earn reward points toward a Target gift card. 

Why would a store encourage price comparing? They don't mind if you find that vacuum cheaper somewhere else: you'll still buy about $25 worth of stuff on your way out the door.