@cinebox Given how cheap it is to get PCBs from Chinese shops, I'm not at all surprised people are using them for coasters. It's super cheap to do a whole panel at a time. Might be a little more expensive to get them to cut the odd shapes. Could have JLCPCB do a panel for you and split them with your friends :D
@cinebox Lots of margin, then. Or maybe they're making them in the US?
$40 would get you like 20 RC2014-sized boards from JLCPCB. Including shipping, which would be half of the cost.