Free Dreamcast games. They were fairly well abused and uncertain to work. I've known the guy running the indoor spot for years, he was surprised he had any as Dreamcast games are prone to death over little marks as he put it. He let me have the 6 I found! Of them 1 (surfing game) was a total goner (as was the top part of the clamshell.) The other 5 working for a good hour using a Novus 1, 2 and 3 level bottle kit I was able to using a microfiber cloth hand resurface much of the wear away. Quite a few curving scratches, scuffs, odd lines and things. Now all (but 1 I did it to) are working it appears. At least I could boot them and play a stage/course or so into them. The resurfacing now has caused a very find plethora of circular/curved microscuffs, but got out the bad stuff...fair trade off to me for freebies.
Ended up with Bang Gunship Elite, San Francisco Rush 2049, Maximum Pool(the clean disc), Hydro Thunder(AllStars), and Army Men Sarge's Heroes. Plan to keep the first three, the other two one is a copy(HT) and the other not a fan of the series. Probably going to stuff em up on ebay or whatever to get my $5 back for the controller.

It's kind of like a few weeks ago when I gamble bought a scuffed up messy $5 copy of Super Magnetic Neo and I was able to buff it into working order.