I've just started playing piano in the last year, since the school I attend has some in its music rooms. Having nothing better to do in between classes and after school, I've been playing for several hours a day 4 days a week. I have some basics down (Beatles, easy classical tunes, and a little bit of improvisation) but I'm starting to get to the point where I really miss not being able to play on the 3 days I have off. I was thinking about buying a cheap keyboard ($60 huntington with 61 keys on amazon

) just so I could practice a bit and work some things out by ear that I hear, and just to play with when I feel the itch to play. But I've read a lot of negative things about keyboards, especially since the one I'm looking at doesn't have weighted keys, and I've heard that these can really screw up your technique. Normally, I could just save up and buy a keyboard, but due to certain circumstances I'll be moving in about a year and will have to leave it behind.
So is it worth buying a cheap 'board? Will it mess my technique up beyond repair? Or should I just practice on the school's real pianos and buy one for myself in a few years?