As above. HSS is in my experience much better than carbon steel, but you do pay for it.
Halfrauds have a 10% online reserve discount until tomorrow Monday 24th Nov, and £10 voucher if you spend £50 or more. I just stocked up on oil/screenwash and stuff which I needed anyway, so now have the £10 voucher for next month, which will go towards something useful.
Their
tap and die set is almost certainly carbon steel I'd guess, but probably reasonable quality.