How to sell to a specific buyer

[disneyshopper]

Create your auction listing, with a very high starting bid.  Contact your buyer with the item number, and have the buyer make an offer with the price you have agreed on.  You accept the offer, buy pays, you ship.

[woodland_gnome]

I recommend using a fixed-price listing with a high Buy It Now which you make Immediate Payment Required (you'll need to use the more advanced listing form rather then the simple one--link to the former at top right of the latter--to have that option) with Best Offer.  This keeps someone else from killing the Best Offer by bidding or committing to buy (unless they actually pay the nuclear price) and you ignore Best Offers from anyone other than the intended buyer.