So you just purchased a hot new smartphone: an Apple iPhone 5, Samsung Galaxy S III, or Motorola Droid Razr HD? The real question is, will you still feel smart when your monthly bill arrives? These days, as household incomes decline, more Americans are spending larger chunks of their incomes on smartphones,  even as they cut back on clothes, entertainment and dining out. PCWorld magazine estimates the total cost of owning a smartphone (the device itself, service contract and data plans) over two years is $3,800.

Maybe it’s time for your phone to start pulling its financial weight. That’s right: Today’s smartphone users can take advantage of a growing number of apps designed specifically for earning cash with the device. Of course, the key to success for using your phone to bring in extra bucks, gift cards or swag is matching your interests with smartphone technology. Here are four apps for building your own Smartphone, Inc., with personality-type to match each one. 

(Warning: If you’re looking to quit your day job, you will need to look beyond these) suggestions.) —RS

1. For shopaholics: Shopkick If you like to shop, check out the iPhone Shopkick app, which allows you to earn rewards just for visiting your favorite retailers.  Buy something, and the bounty gets bigger. Downloading the app, then choose the stores you frequent. The moment you walk through the door of one of them, the app will detect your entry and add rewards points for various promotions and discounts at such retailers as Target, Macy╒s, Best Buy, Sport Authority and Old Navy.  Learn more at shopkick.com.

2. For busybodies: Gigwalk  Have a  buddy who gives you the jump on small money-making opportunities nearby? This app also notifies you of small tasks that need doing in your area and lets you compete with fellow Gigwalkers for the work, e.g., walking store aisles and photographing products or displays; mystery shopping at a retailer; or eating at a restaurant and assessing the experience. Gigwalkers can earn $10 to $50 per gig, and it╒s possible to take on several tasks each day. Visit gigwalk.com for details.

3. For helping hands: TaskRabbit A kind of Gigwalk sibling, TaskRabbit lists tasks such as housecleaning, pet sitting or even furniture assembly. As its Web site boasts, it “connects you with friendly, reliable people right in your neighborhood who can help you get the items on your to-do list done.” How it works: A task is posted, then so-called TaskRabbits make offers, the lowest bid is accepted, and the TaskRabbit is paid (on average, $30 per assignment) when the work is done. Learn more at taskrabbit.com.

4. For goal-oriented: DailyFeats:

This gift-card-earning app has the potential to give the one-two punch of earning while helping achieve a personal goal. By doing things that are good for us, such as working out, saving money, eating a healthy breakfast or even decluttering our homes, DailyFeats offers rewards for a range of products, eBay gift certificates, gift cards for retailers including Walgreens and subscriptions to O, The Oprah Magazine. Visit DailyFeats.com.