As
@Ralston18 noted, these are Kailh MX switches that are 3-pin switches. These will work on any hot swappable PCB board that supports standard switches (not low profile or optical).
As for a cheap mechanical keyboard to use them, we'll need more info on your budget, as you'll have to look at keycaps, as well. Unless you are looking to replace your current switches with these, than as long as they are not optical or low profile, you'll be good as 3 pin is supported by pretty much all PCB's.