By charging money for the application. I'll buy an application for money, but I won't install one that includes advertising code. Or, even, make a trial versio

By charging money for the application. I'll buy an application for money, but I won't install one that includes advertising code. Or, even, make a trial version and allow people to pay to upgrade for the full version. Or do all of the above -- have an advertising version and a version without ads that people can pay for.