He's talking about the classifieds section of Geekhack. People post their keyboard stuff for sale there.
The "Cheat" was a custom board from the Korean OTD community made sometime in 2012, I think. It is rare by today's standards, but still common compared to the custom boards that came before it. Its name comes from a dispute in the Korean community between the nonprofit sub-community and the more enterprising guys. Obviously, they felt cheated when semi-commercial boards showed up using community-inspired designs. (this is a big simplification) Other Koran buys form the same period as the "cheats" include the SOWARE and Rebel keysets. They included keys that said "CHEAT" and "CMA" (copy my ass). There was much butthurt at that time.
It's a very attractive board and I consider it one of the best looking customs. Customs from that period used simplistic designs compared to the latest Duck or LZ designs. I happen to prefer the older ones (KMAC1, for example)
Anyway, the Cheat was a limited run, but they usually show up for sale from collectors every few months. They came in various combinations of red, silver, and black. There may even be a broken one still for sale from Feng, I don't remember if he sold both of his.