The 4-setup for $9.97 + $8.75 shipping (in the U.S., dunno how much to Canada) listing is back:
https://www.ebay.com/itm/152686912359
Or rather, I think he had them listed at the "retail" ~$40 price recently, or he hadn't "rebuilt" his inventory, but they're now back to under $2.50 per 2-deck setup (before shipping). Looks like he has 10 available.