If you’ve been using store rewards cards to save money, your wallet or key ring might be getting a little bit heavy (and not just with the cash you’re saving!)

But if you have an iPhone, Blackberry or Android-based smartphone, a number of apps can (in theory) simplify your life. Let’s take a quick look at three different apps that help you manage loyalty rewards programs and more.

This free app available for all three smartphone platforms has been getting a lot of publicity lately and it seems to be one of the simplest rewards card apps to use. Simply enter your card’s barcode number through the intuitive user interface.

The process to enter a merchant loyalty card if your merchant is not listed in the database is a bit more complicated. First, scroll down to “other” and enter the barcode numbers exactly as they appear on your card. Then, select the “Advanced” option and click “Symbology.” You’ll need to try each symbology to see which one creates a bar code identical to the one that matches your card.

CardStar is constantly adding new merchants to make this process easier, however. If you would like your merchant to be listed, you can make a request at the CardStar website.

When you get to the register to make a purchase, simply select your merchant loyalty card and have the clerk scan your smartphone with the hand scanner.

This popular loyalty rewards card app from Mobestream Media is available for iPhone, Android, and Windows 7 phones. It recently took home 1st place in the mobile commerce category of the Emerging Technology Awards at the CTIA Wireless conference, and it’s not surprising. Key Ring features more than 650 loyalty rewards cards in its database, and also lets you join new loyalty rewards programs right from your phone. You’ll also get bonus coupons from retailers and grocery stores in your area. A store locator function and the ability to backup, restore or print your cards are other impressive features.

Reward Card Wallet from Sundrop is also available for most smartphones. This app lets you easily store all your rewards cards in your phone, and also tracks your location and sends you notifications about coupons and special deals when it sees you are near a participating merchant.

Drawbacks to SmartPhone Apps to Store Your Rewards Cards

Even with the back-up options and added convenience of not having to store and sift through rewards cards, there are a few drawbacks to these apps.

1. Difficult to Scan. Users have complained that sales clerks can’t always scan the smartphone easily. Sometimes this happens if you have a protective coating on your phone. You may also try increasing the brightness of the screen.

CardStar offers step-by-step directions on their website for the best way to scan their barcodes using either a handheld scanner or flatbed scanner, but warns that a laser scanner (vs. an imaging or CCD scanner) may not work.

To summarize their directions:

  • Successful scanning begins with a clean screen and a handheld scanner, although some flatbed scanners work, too.
  • Hold the phone about 2 to 4 inches from the scanner and pull back slowly as the clerk scans.
  • If it doesn’t scan after a few attempts, the sales clerk can enter the code manually.

2. Location-based marketing. All of these apps require you revealing your current location to merchants. It looks like only Rewards Card Wallet actually tracks your location to deliver unsolicited SMS messages to your phone advertising sales. But, as with any loyalty rewards program, (or even surfing the Web), with any of these applications you are surrendering demographics information in order to take advantage of savings.

Education is the key. If you don’t want your spending habits tracked, you have the right to never provide any information to any merchant — and, in return, forego certain sales, bonuses and rewards points. Rewards cards aren’t for everyone, but if you’ve become hooked on saving money and earning free bonuses through store rewards cards, these applications can make it easier.