We did it before, and now we've done it again. Three years ago we proved you could make a personal computer pay for itself within a year. Now it's the smart phone's turn.

Here was the challenge: Could using a smart phone save enough to cover our spending?

We called on some savings-savvy folks who consider a smart phone as essential as their wallet, and also tested one ourselves. Crunching some of their big-ticket deals plus our findings, we figure we could easily save an impressive $1,601, putting us almost $400 to the good.

And it wasn't rocket science. All it took was a bit of time to find and download the apps, those mini-software programs that help you do everything from saving hundreds on a new flat-screen TV to pinpointing the cheapest gasoline in the neighborhood. (Apps are free unless otherwise noted.)

What We Spent:

Price check everything

So you spot that new single-cup coffeemaker and wonder if you've found the best price. Find out in a snap by scanning the barcode. Apps such as pic2shop, PriceGrabber, and RedLaser use your phone's built-in camera to scan a product's barcode, then display prices from nearby retailers and online merchants.

Using RedLaser, Jason Gurwin, co-founder of the grocery coupon app Pushpins nabbed a 52-inch flat-screen television online for $150 less than what a local electronics store wanted.

CouponCravings.com blogger Erin Gifford says barcode reader apps help her find the best prices on small electronics and appliances, plus allow her to negotiate an in-store price match. "I was shopping at Best Buy for a TV priced at $299. I looked up the model on my iPhone and saw it on Amazon for $279. I told the sales associate about my find and he modified the price, no questions asked," she recalls.

Scanning can be tricky (pic2shop helps with a horizontal red bar that turns green when you're properly lined up), but most apps also provide a way to type in the UPC code. Janet Evanovich's latest novel, Sizzling Sixteen, sells for $27.99. RedLaser found it for $14.99, but, even better, pointed out nearby libraries that had it on their shelves. In our book, free wins every time. Gifford estimates saving about $700 a year on her buys. Figure doing at least half as well, and taking the hint to use the library four times.

Savings: $462

Clip cyber coupons

Coupon Sherpa, Yowza, Valpak, and Shooger scour the Internet for discounts or cut their own exclusive deals—typically in the 15 to 30 percent range—with local businesses and national retailers. Type in a zip code or let the phone target your current location. Then the app helps you find coupons by store name or product category. Simply "clip" (store on the phone) any coupons that appeal, then show them at checkout to receive the discount. We dug up $10 off any $60 purchase at Finish Line, 15 percent off anything at The Container Store, and 50 percent off food and drink at a Fort Lauderdale bar’s happy hour. Considering the average American consumer spends about $4,600 a year on clothing, entertainment, and services, even 15 percent off stacks up.

Savings: $675

Reserve a table

Not only does OpenTable (opentable.com) make it easy to find even last-minute reservations (perfect for those "I don't care, where do you want to go, honey?" moments) at restaurants without having to call, but you collect reward points each time you dine. Reservations earns a minimum of 100 points and some places offer 1,000-point tables. Collect 5,000 points and receive a $50 dining check which works like cash at any of the thousands of dining spots affiliated with the site.

Savings: $50

Maintain your balance

It does no good to save money if you can't keep track of it. That's where one-stop financial management apps like Mint come in. Input bank, credit cards, home loan and investment account information. Then the app pulls in your balances, purchases, and stock trades to give you a complete financial picture.

Gurwin praises Mint's ability to help him set up a budget and monitor spending in real time. He can plug in every purchase on the spot, instead of waiting (or worse, forgetting) to do it at home on his desktop computer. In fact he's gotten to the point where he almost never pays in cash, instead using a credit card even for tiny purchases. “I love that it lets me track every expenditure so I know if I’m sticking to my budget or going over in one area," he says, "and it reminds me when my credit card payment is due."

Mint's reminder emails and text messages about upcoming bills or low account balances can help you can avoid overdrafts, bounced checks, and late fees. Says Gurwin, "I've had Mint notify me of a $15 service fee on my checking account. It was a mistake and I was able to get the bank to remove the charge immediately." Figure twice a year a bounced check costs you $30 and overdraft fees are $27 per oopsie. 

Savings: $114

Fill 'er up

GasBuddy ($2.99) shows you the nearest gas stations with lowest prices in your city, plus has maps to guide you through unfamiliar territory. A check on Atlanta lists the 15 highest and 15 lowest prices (a span of nearly 50 cents when we looked) within the past 24 hours for the city and its suburbs. Driving about 15,000 miles per year in a car that gets 25 mpg means pumping about 600 gallons of gasoline.

Savings: $300

Bonus round

Add 'em up, that's $1,601 in savings in your first year using a smart phone. And we didn’t even count one simple act that doesn’t require a single app: unplugging from the wall. The average landline runs $25 a month. True, it's a bit scary to disconnect, but do you really need two phone numbers? Discontinuing your service nets yearly savings of $300. And these days every bit helps.