First, congratulations on making something people want. If people are requesting more exercises it probably means you have a user base that: a)cares about your product and b)wants to see it continue. Yes, going after schools is hard, but going after teachers may be easier. There was a HN post a couple of months ago about a student grading application someone here had created and in trying to sell it, he ran into similar difficulties with targeting schools. But what he was finding was that teachers valued his application enough to purchase it themselves, then they would tell other teachers at the school, and pretty soon the whole school signed on. I think you should focus on keeping your product at a price point that would allow teachers to purchase it themselves. Maybe even try to build in some social features that would encourage teachers to spread the word. Then, with the revenue, outsource content creation. Finally, once traction and revenue reach a point where it makes sense for you to leave your full-time job or hire an additional developer, add functionality that would appeal to entire schools or school districts. Also, congratulations on the little hacker on the way!