Recently I bought a Gamecube Broadband Adapter, which I'm still debating on keeping or taking back. It was the only one I have ever seen so I had to pick it up.
Other purchases:
Super Puzzle Fighter II Turbo [PSX] -- $6 / used
GunValkyrie [XBX] -- $15 / new
Final Fight One [GBA] -- $10 / new
Caesars Palace 2000 [PSX] -- $10 / new ... Don't ask. I thought it'd be fun to have some casino games to play every now and then. Well, it's not that fun.
edit: I forgot about Sonic Adventure 2 [JPN/DC] and Fire Pro Wrestling D [JPN/DC], both of which were ordered, but havn't arrived yet.