I'm thinking about getting a 3D printer as well. I actually have use for one, being in the model aircraft/multirotor hobby I often have various specific parts that I'd like to print - currently I use the printer available in the local hackerspace, but it's mostly booked full for weeks in advance, and they never have the filament in the colors that I would like to use. Having one at home would allow me to rapidly prototype and produce parts as I draw them up, instead of having to wait forever first. Some of the parts I print I could also sell, I've designed a few things that people on the local multirotor forum have already asked me about being able to purchase... it's at least worth giving it a thought. Now if I only had spare $500...