Anyway, if you’re like me, you’re always looking for a way to reduce the number of things you have to carry around. Likewise, if you’re like me, you’re constantly trying to make your iPhone be the only thing you have to grab when you walk out of the house. If the DMV ever lets you get a digital driver’s license app for the iPhone, my wallet is history.

I picked up the latest in wallet- and keychain-reducing apps yesterday, and believe me when I tell you that this is bound to be one of my most used apps.

Currently, I’m a Blockbuster Total Access subscriber. All my friends use NetFlix, but I use Blockbuster for a couple of reasons. One, I can take movies I’ve received in the mail and exchange them at the store for an instant free rental. I used to be able to get the next movie in my online queue immediately, but they’ve since changed that behavior so that you can keep the movie rented from the store for as long as you want. Second, I get two free video game rentals every month. The rentals can actually be used on anything in the store, but I prefer to rent video games, as I already get plenty of movies. Before I go to the store, I download the coupon to my iPhone (as it’s just a bar code generated as a JPG). Some days, if the iPhone feels I am worthy, the clerk can even scan the barcode right off my screen instead of typing in the number. Of course, I still need to get my Blockbuster card out of my wallet so it can be scanned, otherwise I can’t actually rent anything.

Enter CardStar. This application lets you pick any of those pesky little keychain shopper discount cards, membership cards that have a barcode on them to scan, and really any other series of letters and numbers you’d like, and store them on your iPhone, where they can be scanned right off the screen. Sounds cool, right?

So far, the only drawback is that the app doesn’t always succeed at automatically deciding which barcode language it should display it in. But, as long as you’ve got the original card, it’s super-easy to just test the different options and examine the card to see which one matches. I haven’t tested it in the real world, yet, but I have scanned the images with the barcode reader on my computer to determine that it works perfectly.

The catch? Some cards don’t say what the number on your card is, requiring you to either know how to read barcodes yourself, or have a barcode scanner on a computer that you can use to determine the correct numbers to enter into your iPhone. Still, though, if it just gets those pesky member discount cards off your keychain, I’d say it’s worth it.

Also, it’s free.