35 BUCKS? I got one from Nashbar for about $8, and since I was ordering other stuff the shipping was no big deal. I think they list it as a sprocket removal tool. The vice grips and a length of chain sounds like a great idea. You only need the chainwhip for a second, just to break the lockring loose. In a pinch I have managed just by using a wooden dowel, board or other non-marring item stuck in the space between two teeth and blocked by the chain stay with a rag or something for protection. DON"T apply so much pressure you damage anything. If it doesn't loosen pretty easily, STOP and try something else. Just about anything that allows you to block the cassette from turning, without damaging anything like a spoke or the frame, will work. I think I've even gotten enough grip just by hooking a tooth with the hole at the base of an adjustable wrench handle. It shouldn't take too much unless whoever put it on went all King Kong on the lockring. When you replace the cassette it's not necessary to tighten the lockring extremely, just get it good and snug with what might be termed moderate pressure.
FWIW,
Raymond
__________________
If it ain't broke, mess with it anyway!