hi all.
i'm a new macbook user, in fact i'm new to mac os x. i've check it's RAM, it said only about 200mb free? whoah that's too low, is it? (compared to windows system i've used before, always like at least 800mb free). Should i consider upgrade to 4 gig? if so, how much should that cost me? can i just buy ram from pc shops and upgrade it myself cuz i think that would be much cheaper.

Sorry if someone already bring this topic earlier, but i couldnt find it.