dylan said:
I was more interested in people who have had good experience getting it off of ebay etc. just because money is really tight. Is it worth the risk?
Unless the seller says it's on DVD-Rs or something, I would have to say you'll be okay.
Unlike hardware, it will be pretty easy to determine whether or not it's "broken" once you get it.
Buying Tiger through eBay, you can only assume that the original owner has uninstalled his/her copy. If they haven't, it won't affect you at all and you'll be blissfully ignorant.
Basically, if you can find a good deal, go for it!