Over on amazon.com, there is a reprint of the "Dungeons of Dread: "S" Series Classic Adventure Compilation: (S1 - S4) (D&D Adventure)" in hardback that can be had brand new or for a lower priced in used condition. Find out more here.
Also, on amazon.com, they have "Against the Slave Lords: "A" Series Classic Adventure Compilation: (A0 - A4) (D&D Adventure)" also fairly low in used condition. Bookmark the page if you want to wait until they drop a little more here.
Finally, on eBay, someone is selling "B3 Palace of the Silver Princess **Ultra-rare original orange edition**" and the bidding is around $1,5000.00 at the time of this posting. See more here.