The Solution: If you're an Android user, Murph suggests taking advantage of the trial period provided by the app store, which lets you download an app for a certain amount of time before you either pay for it or let it lapse. If you use the new app every day, great! If not, poof! It disappears at the end of the trial.
Windows or iPhone users can take an inventory of most-used apps. Then, pick one app category on which you're willing to spend money, and as for the rest, promise yourself that you'll look for free alternatives. For example, if you really like having Mint on your phone so that you can get text messages about spending, or if you're deeply attached to Evernote because it syncs notes that you make on your phone and your computer, then you'll want to spend on utility apps. So reserve your splurges for the next great one that comes out—and stick to the free version of Angry Birds.