Saying no

[spronk]

rich/powerful people get gifts for people who do them favors because it "evens the score", if they didn't then they would "owe you one". Nobody likes owing someone else a favor.

So if you repeatedly and insistently say no you are basically telling him "nah bro, i'm going to expect payback later though when I need a favor". Take the gift, ebay it, and move on.