I got a bunch from Tractor Supply Company about 10'ish years ago for a room in our house for the wife to train, and hell yes, they suck moving around! lol
They are good quality though. I took them out of the house and used them on the cement flooring in the shed I built...as she wasn't even using them in the room...and also that room is now for our daughter.
I just ordered a 800-1000# squat rack that should be coming in next weekend. I'm gonna go buy some more mats to use under the rack on our patio...hopefully TSC is open though...