Once the app is out there, you do want people to give you money eventually. The key to this is having purchases inside your free app. For a game app, this could mean additional levels are available only for a fee. For other apps it may mean that people have the option to purchase your products and services through your app. No matter what, you need to have something in your app that motivates people to make purchases after they have downloaded it. You can also create two different versions of your app -- one that is free, and an improved version that costs money. This is very popular with companies that create app games. The "lite" version usually has limited options and levels but is fun enough to get people addicted to it. Then, when they want to play more or get stuck on a level, they'll be willing to upgrade to the paid version so that they have more options. Finally, you can insert paid advertising into your app. There are many companies that are willing to pay app developers to put ads into an app. They know that people use apps regularly and want the additional exposure. So, see if you can find people who are willing to let you put product placement in your free app.