Best used camera for a beginner?

Here is what the site says about that.

From Your first camera: Don't overthink it: Every current camera from a major brand is good. The differences that matter for a beginner are size, handling, and which lenses the mount offers. Hold a few in a shop if you can, pick the one that feels right in your hand, and buy it used if you want to save money: see buying used.

From Buying used: Buying used: Cameras and lenses are built to last, and many photographers upgrade often. That makes the used market one of the best ways to afford good gear. A body that's one or two generations old is often most of the camera for a fraction of the price.

Quoted from this site's pages.