I had both my knees done, I think it was AUD$400 because it was GP not specialist referred. Probably one of the more expensive things you can get done in this country, but I'm thankful it was only that much hearing from the yanks.
Like... For your pet hamster or for research? Cos the only rodents I know who get a MRI done are for research. And then the people doing the research own the MRI.