Should I buy a used Nintendo 64 with a loose joystick?

Only buy it if the issue is limited to the loose joystick on the controller, and the price is discounted enough to cover a replacement or repair. A loose N64 thumbstick is incredibly common due to wear on the original plastic gears, but it makes games like Mario 64, GoldenEye, and Smash Bros. feel noticeably worse and harder to play.

Best call: treat the controller as defective and price out a replacement joystick assembly (which is cheap and easy to swap with a screwdriver) or a new controller altogether. If the console itself works, the video output is clean, and the seller includes the original cables, it can still be a great buy at a discount. If you cannot test the console, or if the seller is pricing it like a fully functional bundle, you should pass or negotiate.