Costco (in Canada at least) has these sweet rubber mats that remind me of the gym. Way cheaper than Amazon since they are heavy as heck! It's flat on the other side :
Sportfloor/Fitness - Armour Rubber
Rubber Flooring Rolls - Rubber Flooring Direct
Home Gym Floor Mats - Exercise Room Flooring
Rubber Rolls - Armour Rubber
Rubber Gym Flooring Canada | Gym Floor Mats and Tiles
IncStores 4'x6' Premium Mat - Vulcanized Rubber Exercise Mat, High Density Floor Mats for Gym Flooring, Home Gym, and Horse Stall Mat (Gray, 3/8" Thick - 1 Mat), Exercise Mats - Amazon Canada
Gym Flooring Canada - Home Gym Floor Mats
Interlocking Floor Mats - The Quickest Way to High Performan – Sprung Gym Flooring
Interlocking Rubber Floor Tiles Canada - Buy Floor Tiles Canada, Gym Puzzle Rubber Tile, Interlock flooring Product on SOL RUBBER
Sundance Mat Straight Edge Standard 3/4 Inch - 4x6 Ft.
Premium EZ Rubber Gym Mat - Grey - MAXUM fitness - Home Gym Fitness Equipment Retailer