Whether you need to keep receipts for business or personal use, one way to forgo stuffing paper receipts in your wallet is to take a picture with the phone's camera. While there are several apps that track expenses this way, I like the simplicity of Lemon, which launched this month (Oct. 13). Take a picture of the receipt, tag it with a category and then if you need it later for a return or expense report, just pull it up on a mobile device or print it out. The basic service is free. Custom reports and exporting data is $7.99/month or more. Available on iOS/Android (free): Check out the Lemon app here.