Stay away from ads
If you put ads into your software, then it becomes "adware", and such apps are seen as spamware. Your app will either not be used or quickly replaced. People and schools will treat it with suspicion and be disinterested. Plus with adware, you'd have the added problem of making the software connect to the internet to update the ads. And this will trigger alerts and firewalls from protectionware. You mentioned selling it as an idea. If you sell it for a low fee, schools may buy it. Another way to monetize it is to include a link to your website in one of the pull-down menus, such as About or Help, but seen in a part of the menu they'll use. Then monetize that traffic on your website instead. Ads are always the lowest way to make money and the detract from perceived value of your site. So you can market your own products on your site. Or you can place affiliate links as part of the content of your site, not as interruptions like ads, but as part of adding real value to the visitor.
