Originally Posted by robo
re. using the lockring from the old cassette
So the question still stands: how much should i expect to pay for one?
New lockrings come with every new cassette, so if they're nice, they'll give a used one to you, or save one for you from an old cassette they change out.
If they're not so nice, I'd say a couple of bux (<$5) would be a fair price for a used one.