Amazon has this Stansport T-810 Reinforced Multi-Purpose Tarp
For $6.13 as an add on item.
Made of durable rip-stop polyethylene laminated on both sides
Size 8 X 10-Feet, Rope reinforced edges
Heavy duty rust resistant grommets every 3 to 4-Feet
Waterproof, washable and shrink proof
Color, Forest Green
Recommended for light to medium duty use. Results may vary based on seasonal elements such as sun, wind, and rain
Sizes listed are cut sizes. Finished sizes are about 6” shorter in each dimension