I want to alert you to an app I've been using for quite some time and I think YOU need it. Be advised, I am not affiliated with or sponsored by the creators of Key Ring in any way, so this review is completely unbiased!
"So, what is this app I need" you ask? Let me explain the way I understand the iPhone version. It's called Key Ring and it's available in apps on multiple platforms. All your loyalty cards (those pesky things everyone wants you to weigh down your key chain with) can be scanned into this app. EVERY ONE OF THEM. No more cards filling up your wallets or weighing down your key chain. You scan your card, verify the number scanned correctly, name the brand if you didn't find it in the menu and BAM. When you go shopping, you whip out your iPhone (or other device as appropriate), pull up that app, and give it to your cashier to scan at checkout.
Want more? Key Ring will also tell you about specials/promotions (though it doesn't tell you about all of the sales, so you still have to do your research).
Also, plan to keep your cards handy - I have found somethings still require the magnetic strip i.e. Winn Dixie card when using fuel perks at a participating Shell. And, should anything ever happen that I need them, I've ditched so many I wouldn't want to have to start over! Just my advice.
Get your Key Ring app at keyringapp.com NOW.
Do you have any insight on the other platforms? Speak up here!