For a grand total of $109, I made the following steal at the Fantasy Shop's Used Gaming Auction.
1981 Basic and Expert D&D Books
B2 Keep on the Borderlands
X1 Isle of Dread
1984 Mentzer Player and DM Companions
AD&D: Fiend Folio, Monster Manual, Monster Manual 2, Oriental Adventures, Dragonlance Adventures
AD&D 2E: Players Option Skills and Powers, Players Handbook, Complete Thief's Handbook, Complete Book of Humanoids, Arms and Equipment Guide, Players Guide to Dragonlance, Dragonlance Adventure: Dragon Keep, Dragonlance Adventure: Wild Elves, Dragonlance Accessory: Time of the Dragon, Castles Box Set (with fold out castle, wtf?), Fritz Leiber's Lankhmar box
3.x D&D: Players Handbook, DM Guide, Monster Manual (all three for $4!), DM Screen, Pool of Radiance: Attack on Myth Drannor (came with B/X/B2, weird I know),AEG's "Magic", Bastion Press' "Friends and Familiars", Encyclopedia Arcane Crossbreeding and Familiars
Dragon Magazines: 169, 200(!), 233, 302-4, 306-8, 311-15, 351
AD&D 2E Monstrous Compendium Volumes 1 & 2, the binders, including appendices from Kara-Tur, Spelljammer, Outer Planes, Forgotten Realms, Dragonlance, and Greyhawk Adventures
Role Aids Adventures: Wizard's Betrayal and Clockwork Mage
Oh, and Heroes Unlimited and Ninjas & Superspies, because why not?