What type of HRM should I get?

fatfiske

I'm considering getting a HRM so I have a better idea of what type of calories I'm burning, but not sure what type to get. I like the idea of a the watch type, but if armbands are the best way to go, i don't think it will bother me too much. Also, I really don't want to have to spend a lot of money on it, I'm a law student and money isn't exactly free flowing. Any suggestions would be great- thanks!