** eBay auction listing blocked. Please enable cookies in your browser for this site and for eBay! **the one you have here is art by Larry Elmore and came in a pack with one other sheet/board.
One of these sold last May for around $64, but it also came with a similar sized high quality B&W photo print of it used for the production. It was sold on behalf of Jim Roslof's wife, Laura, who also worked for TSR.
There is a thread here about these Pen & Poster sets
Advanced Dungeons & Dragons Giant Pen and Poster set 1982