I'm just talking out of my ass because it's new and I'm into it right now, but for a cool looking game room at a reasonable price, a guy could build himself a long, sturdy counter, then collect some of those countertop cabinets. The countertop cabinets seem to average in the low $200s, so you could buy 2-3 of those for every one full sized cabinet.
While it's way cheaper to do a CPU mod and get a "universal" controller plate with buttons and joysticks for all the games, having specific cabinets with matched controller plates all lined up would look cool in a man cave.