Thanks for your advice. There are couple competitors on a market right now ( launchkit.com, storeshots.net etc. ) and they have richer functionality than my service. So i'm not sure why people would pay for my app rather than for theirs.

Busy devs aren't going to do a competitive services search... they're going to use the first tool they find / hear about. Focus on SEO, SEM, offer a free demo mode with watermarks, then charge around $5-10/mo recurring for unlimited usage for solo dev (maybe $20-30 for team use), and you'll be golden.

If those are your only true competitors, you SHOULD start charging. I like storeshots per credit charge.. instead of a monthly charge.

btw, launchkit redirects to : communautic. com ... looks like they were hacked.

Because the features they are offering may not be something a prospective customer values.