I saw the post below about diamond cutting off wheels. I actually have a few. I use them in just certain places. If I think there is any chance of the wheel binding or some other instance where it will be damaged I use normal wheels.
The best value for the money( not just the cheapest I can find) is Benchmark Abrasive wheels I buy through Ebay. I use the 4 1/2 x .040 with 7.8 arbor hole, flat wheels. These are rated for stainless and regular steel. Cost with shipping is %59.95 for a box of 100. So sixty cents each. They last pretty good for a cheaper wheel. I like them because you can break a wheel and not break the bank.
https://www.ebay.com/itm/100-Pack-4-5-x-040-x7-8-Quality-Thin-Cut-Off-Wheel-Stainless-Steel/280506610924?hash=item414f7f34ec:g:tFcAAOSwd0BVt-qy
4 1/2 cutting wheels on Ebay
The best value for the money( not just the cheapest I can find) is Benchmark Abrasive wheels I buy through Ebay. I use the 4 1/2 x .040 with 7.8 arbor hole, flat wheels. These are rated for stainless and regular steel. Cost with shipping is %59.95 for a box of 100. So sixty cents each. They last pretty good for a cheaper wheel. I like them because you can break a wheel and not break the bank.
https://www.ebay.com/itm/100-Pack-4-5-x-040-x7-8-Quality-Thin-Cut-Off-Wheel-Stainless-Steel/280506610924?hash=item414f7f34ec:g:tFcAAOSwd0BVt-qy
4 1/2 cutting wheels on Ebay