Mark,
Having actually delt with that ring I think $90-$100 is still WAY to much to pay for that thing. It's just a goofy piece of metal and not very substantial at that. I guess the price comes in when they have to machine/cut/cast all those little peaks and valleys into the ring.
I say try and find it in a U-pull-it yard...it's not like they go bad.
"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong, it usually turns out to be impossible to get at or repair."
-Douglas Adams, Mostly Harmless