First thing.....I would not recommend buying a bow off Ebay. Go to a dealer and let him set you up with a used one that fits. At least you can shoot it a few times and get an idea of what you are buying. It just seems to me that Ebay would be a good spot to unload a problem bow....bent riser, cracked cam or limb, etc., etc.,.
Reputable dealers normally have a good selection of trade in bows or bows that they are selling for someone on consignment. You can usually cut you a good deal. Buying a used bow unseen is just plain risky IMO....especially when it is being shipped across the country.