Ever wonder how much you've spent on apps, music and videos? SpentOnApps keeps track of all your iTunes Store purchases, and sums up all the amounts. Your spending is presented beautifully, and you can tilt the device to see a graph of your spending over the last 10 months. It also lets you see each item that you have purchased.
All you need is the email account you use in iTunes and it must support imap. If you use Gmail, Mobile Me or AOL you can just type in your email address and password, and the app will set up everything for you. Of course you can also share your spending with your friends on Twitter and Facebook.