How did I do this?
First of all, I searched craigslist for cheap PCs that were old and needed some work. My range was between $30-$50. I spent $600 on machines. Mr. Young and Mr. Winegarner donated some ancient machines that they had sitting around along with monitors.
The biggest task was making the machines functional, but overall this was not much of a chore. I simply abandoned windows, and switched to lightweight linux operating systems (zorin and lubuntu).
The installation is simple. Plug in a USB or a CD and boot it up. If you're not sure, then there are hundreds of linux installaiton videos on youtube to help you out. The OS is very similar to windows xp. My students have not complained once about linux once. They figured out how it worked pretty quickly and they enjoy the speed.
Trust me, these are ANCIENT machines. They were in their deathbeds. Now students can do everything a modern windows 8 system does - and probably better.