What cooler should I get for tailgating that I can also sit on?

Get a rotomolded cooler like the Yeti Roadie, Engel, or RTIC. They’re expensive but won’t wobble, crack, or sweat condensation. The 20-quart Roadie is a good size—holds a case of cans and is easy to carry. Engel and RTIC make nearly identical coolers for less. Avoid cheap coolers that flex and leak.