What's the best way to out Revised Duals?

I currently have an Underground Sea listed on ebay (MP/HP, asking $250), but I've never attempted to move a card this valuable before -- any advice appreciated. The 10% sellers fee seems especially rough on a large sale like this, so I'm not sure if ebay is right. I'd like to take advantage of the recent spike as best / as quickly as possible though. I've seen FB suggested before -- are there any groups in particular that I should look into?