We have found the opposite - teachers will pay for software if it is made well and makes their life easier. The price point obviously still needs to be set appropriately.
Life was very busy when I was teaching, anything that saves time on busy work is appreciated.
The crap results were probably due to the soldering messing around with the crystal properties. Using a pressure-contacts approach instead seemed to do the trick:
I use it once every couple of weeks to tweak seating plans for my classes as I discover new relationships between the kids.
Desktop software because the SA algorithm placed too much load on the server, it started off as a Ruby web-app. Also desktop because most school networks have pretty draconian filtering in place.
Life was very busy when I was teaching, anything that saves time on busy work is appreciated.