As others have asked, what's your current printer?

For your money and school application and pure learning value you'd want to look at FDM/FFF machines (same tech really). I'd avoid any printer that only uses ABS as a filament as the fumes aren't pleasant (personal experience). A lot of the strength and quality aspects of a 3D print depend on the design of the part, some people perceive that 3D printing can create anything first time perfectly, I'm sure you have experienced this isn't the case.

I'm currently looking to change my printer UP! original, as it is a few years old now and I need something a bit more modern for what I want to do, I'd steer clear of the UP brand btw they come out top in reliability tests but other areas, build volume, software lets them down. I guess you could either go for a one big build area printer or 2 smaller ones just an idea.

I'd really recommend buying and reading this review magazine, they thoroughly test all the printers and give honest reviews - note it says the UP2 wins for reliability :P http://makezine.com/volume/guide-to-3d-printing-2014/

Alex