Would you shop at a place with this sign? "We beat all competitor's prices."
Yes. I don't see an error. 8 (8%)
No. I refuse to shop at places that use apostrophe errors. 21 (22%)
Yes. But I wish the shop would fix the error. 66 (69%)
"All competitor's" is not possible. "All" suggests more than one; "competitor's" suggests one. The store should change its sign to "all competitors'."