Got my biggest haul is ages at an auction about 45 minutes away. I ended up paying more for it than I had hoped, because it didn't go up until the end, and the guy I was bidding against didn't show up until the end, but it was still not a terrible price.
$250 for a in the box NES Deluxe Set (and about 40 other games). It was complete aside from Gyromite and the inserts, which I already had a copy of. So I now have a completed boxed original NES set, and I am pretty stoked about it.
The 40 games was mostly commons, but about 20 that I didn't already have, including Contra. But it also had the full Mario trilogy, Metal Gear, Bionic Commando and Clash at Demonhead.