what could happend to 500.00 in microsofts stock?

how do stocks work? if i put 500.00 into microsoft.. what do think it would look like next year?? i mean, im thinking about doing it, but, im also going into the military and will not be able to do anything with it untill late june 07... i somewhat know how it works but, im not to sure.. and i was just wondering if it was worth it or not.