This is the opposite of the truth for small businesses: you can sell to any teacher, all you have to do is convince her to get out her credit card. To sell it to a district, you're going to have to go through a sales cycle measured in months to years. You will have to collect rubber stamps from upwards of four different decisionmakers, three of whom have no interest in using your software, at least one of whom has incentives to kill the purchase.

Selling software to educational institutions is largely a matter of playing Enterprise Sales. I don't suggest you make that choice lightly.