Glad to see you are picking up a bow. There is one huge down fall to a new bow shooter, and ebay. You will get much better help and getting the bow set up if you purchase from the shop. The shop does not want bad feed back and will normaly get you set up free of charge and it will be right for YOU. Chances are you will not be saving much at all by the time you have the draw fitted to you and everything else set to your style. If you have a buddy or something that can get you close, then you may be OK.
My second bow I bought was throough a shop, when I left there I was comfortable and confident of my equiptment. Thats been worth more than a couple hundred bucks to me.