You want a 100$ tool. Impossible. Toshiba and Toshiba OEM are undocumented, so AFAIK only 2/3 tools can work on them and with BIG limitations, too. Few people (

) have developed independent knowledge. Solution: send to such a laboratory the drives for mass repair (only the ones that have repairable surface problems). You have less hassle, everyone work, everyone is happy. This works only for medium/big numbers, not for bedroom based business(es). Otherwise, you have to find a source for the spare parts at an acceptable price. The problem is that in your business model the average customer is lowest target, no money. And I haven't touched the TAXES ARGUMENT.
P.s. Ninja and similar are cloning tools, not for fixing.