I chose one of the less expensive floor mats as a beginning point. This one would be fine on low pile carpet with very thin or no padding. I am not heavy and the chair wheels sink into the mat and into the padded carpeting. The good part is the mat is sturdy enough it has not cracked in the 2 1/2 months of ownership.
Works ok. If you sit in one place for a long period of time the wheels on the chair sort of sink in making it a little difficult to move. At least it isn't cracking like the one I had to replace.