The little motor in our bathroom fan failed a couple years ago, and I just ordered a new motor on Amazon. The fan assembly is a Ventline brand and this was the motor for it. It was pretty easy to replace, no need to cut any wires as the wire connectors are just tiny spade connectors and the fan just pulls off the splined shaft.
https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1