Ebay is ok if you know EXACTLY what you want. Personally,I would NEVER buy a bow I couldn't shoot first, and that includes one from a buddy. We see horror stories at the shop all time. It goes something like this:

"I just bought this bow from a buddy of mine. I got a great deal on it, but the draw length is too short. Can you make it longer?"

Sometimes we can, but most often we can't. The moral of this story is this. Had that same guy SHOT the bow before he bought it, he would have known that and not wasted his money. Same w/ mail order bows. Unless you've shot the brand and make of bow you are buying, it's just a stupid move. If you know nothing of the bow you are purchasing, I can all but guarantee you that you won't be happy with it. Ok, I'm off that soapbox now.

Head to the shop. Tell them your budget, and see what they can do for you.