Almost the worst garage sale tap marked HSS will be better than those department store carbon steel taps. I bought some lousy ones at Lowe's and complained to the manufacturer. They sent me a new set, which I promptly gave away. One of the taps tapped large, and some screws wouldn't engage.
Internet wisdom says that the cheap carbon steel taps shatter when you hit them with a punch, so they can be removed easily when you break the tap in a hole. This is NOT true. I suspect that this factoid came from the observation that vintage fine gunsmithing carbon steel taps can be shattered with a punch. The cheap ones definitely cannot and will cost a carbide endmill to remove.
Buy taps one at a time from an industrial supply store. The guy who goofed up the hole ended up going to Fastenal. One tap cost almost half the price of the big box set. Furthermore, it was made in China. Didn't matter. It was name brand, HSS, and fine quality. The Lowe's taps were made in the US. If you looked at them side by side, you could see the difference in quality. Scary.
