I am an adult. I have a job. My wife has a job. We have iPads, iPhones, and, (most importantly), disposable incomes.
If I like a service or product that you provide, I will pay for it. Please let me pay. I'm tired of free, ad-supported apps, services that go under after 6 months, buyouts, and talent acquisitions.
Don't be scared to charge your customers and take the money.