Walmart offers Red Dead Redemption: Game of the Year Edition for Xbox 360 for $10. Opt for in-store pickup to avoid the $5.97 shipping fee. That's tied with yesterday's expired mention as the lowest price we've seen. (It's the best deal today by $5.) This last-gen classic includes the base game and the Undead Nightmare expansion.
Note that this game will also work on Xbox One consoles via backwards compatibility.