For years I used an old length of chain. Never had a problem, just grasp it with a visegrip. That being said, I recently bought a chain whip because I realized that they aren't all that exspensive. Tools are investments and as a former auto mechanic I can attest that good tools are worth the cash. Either buy the tool or pay the guy with the tool. I agree with Sweetwater, I have plenty of bikes and extra wheels so I'm always swapping cassettes around so it's handy to have.