Used Tractor Values

preferably used and in fair to good condition

A friend of ours has recently bent his Front End loader bucket on his Kubota tractor. I’m talking about the think in the front of the tractor that picks up dirt from a pile and moves it, basically.
I have searched and searched and cannot find a replacement bucket for it. Where can we buy one (new or used)? Does it have to be a Kubota? Also, what is the price range that he should expect to pay??

I’m considering a Massey Ferguson model 90 front-end loader for sale, to attach to my Ford 2000 tractor. How can I find out before buying if it will fit my tractor?