Three ways your smartphone can lighten up a heavy wallet

Despite the fact that I conduct a biweekly wallet cleaning session, my leathery companion still overflows with stuff.

The phenomenon is so frustrating, actually, that it inadvertently causes me to lock up when a sales associate offers me a rewards card, a colleague excitedly gives me his business card, or a cashier hands over a 10-foot-long receipt, complete with coupons and offers. Ugh.

Even though many analog items like address books are now obsolete, these other paper and plastic things have yet to join the transition into digital.

To be fair, some retailers are ditching physical rewards cards and opt for a phone number instead. Apple is also paperless, and e-mails receipts instead of printing them. These retailers' switch to digital is commendable, but until more merchants become aware of the 21st century, these smartphone apps will help lighten the load on your wallet.

Replace membership, loyalty, and library cards with Key Ring.
Brick-and-mortar retailers will do anything to keep you coming back for more--rewards dollars, a free sandwich, arbitrary points? Some of us would like to believe we're too educated to buy into these things, but anything "free" is hard to resist.

As such, these membership or loyalty cards are often the top perpetrators that weigh down your wallet, especially since they're often made of plastic.

That's why Key Ring, a free app for iOS, WP7, Blackberry, and Android, is so useful.

The app simply asks you to scan the bar codes of your membership cards and enter a couple details about the retailers. Key Ring will then create a digital, scannable version of those membership cards. The next time you visit a store like CVS, open the app, tap the card, and the cashier will be able to scan it from your smartphone's screen.

As a bonus, Key Ring lets you know if you have any offers from your rewards cards, and also lets you sign up for new memberships with other nearby retailers.

Note that even though many retailers will have no problem accepting membership or loyalty cards via Key Ring, membership cards with your photo on them will have to stick around.

Scan and store receipts with your phone.
One thing is certain: brick-and-mortar stores that struggle to compete with e-commerce sites do a pretty good job at making returns difficult. Return policies vary in detail, but they all begin by requiring a receipt.

It's going to take some habit-forming, but Lemon (free for iOS, WP7, Blackberry, and Android) aims to eliminate a pocketful of paper by allowing you to scan, tag, and organize your receipts on your smartphone.

Doing so is painless. Simply launch the app and tap the camera button. You'll be asked to take a photo of the receipt, give it a category (like business, personal, food, etc.), and it will be stored in the app and sorted by date.

If you need to make any returns, many retailers will accept a digital version of your receipt. All the cashier needs is the bar code (which is scannable from your screen) or the receipt number, which will also be visible.

Nonetheless, you should stash the physical receipts somewhere safe just in case.

Digitize business cards and connect online.
Whenever someone hands me a business card, I have to stifle a disappointed groan. With the advent of Twitter, Facebook, and LinkedIn, there's certainly a better way for us to connect immediately and keep in touch in the future.

And now, with online customization tools and fancy cuts, business cards are more awkward and burdensome to store than ever. The solution? Smile and say "thank you" to the person dispensing her business card, admire it for a moment, then digitize it with CamCard.

The app for iOS, WP7, Blackberry, and Android acts as a Rolodex, allowing you to archive business cards by taking a photo of them. The app will then transcribe what's written on the card so that you can quickly search for a contact when it comes time to reach them. From their digitized card, you can contact them via phone, e-mail, MMS, or add them on LinkedIn.

If you're a dedicated LinkedIn user, check out CardMunch. Once you take a photo of a business card, real human beings on the other end will transcribe their contact information, find the person on LinkedIn, and invite you to connect with them. Good thinking.