Regular plastic placemats. Walmart $1-2.
I laminated sheets
I use a large silicone mat. You can get an acrylic clear table cover but because I make my own playdoh it’s more doughy like and less sticky like the plasticine playdoh. If you don’t want to buy a new mat try making your own playdoh it’s super simple and cheap and we get a lot more out of it, lasts me 8-9m I make batches and keep it for play date favours like when kids come over and then leave I have a lil something cheap to give them
I use cookie sheets :)