not saying the OP is definitely scamming, but if he were this is how the scam works.
you list the item on ebay and sell it for say $500.
you send him $425 and keep your $75 (15%)
the item never ships and you are on the hook to refund the buyer $500.
OP vanishes.
only way I would do this is if OP agrees to wait until the seller has received the product and left feedback before he gets paid.
good luck and be cautious anyone who decides to try this.
Need a Verified Ebay seller account pm me or comment here