Can you tell me what model it is and it's worth?
Ken-Bar SD-9. Says so right on the sticker. It looks mostly complete except for (maybe) the engine. 50 bucks is a killer deal indeed!
The “9” means it was originally a 9 horsepower engine so yours has a 9HP already. All the info is there on the sticker, it’s American made.
It’s worth whatever someone is willing to pay. These American fun karts have not approached the prices of, say, a Rupp kart or similar from the 1960s but maybe in time they will.
Edited to add: “SD” stands for Sand Dog so this was a direct competitor to the Manco Dingo of similar frame size and engine displacement.