A good price: A good wireless controller usually costs somewhere between $40 and $60, and a decent wired controller should cost around half that.
But compatibility with macOS and iOS (and the Apple Arcade service) is a plus, as is support for game stores like Steam that offer their own controller support.
Everything should be easy to reach, and the buttons should have enough space between them for you to find them by touch without accidentally pressing multiple buttons. The controller should also feel substantial but not so heavy that it causes arm and wrist fatigue.
