The answer for just doing a few things in your lifetime is basically "whatever". I got my M6 taps decades ago from RS. Even a reputable brand 3-piece set (lead, second, bottom) of M6 hand taps is going to be under £20 and a tap wrench for small sizes is about £10. To be honest, going into aluminium or soft steel you can probably get all your lifetime needs out of something cheap off of Amazon or ebay.
The answer for just doing a few things in your lifetime is basically "whatever". I got my M6 taps decades ago from RS. Even a reputable brand 3-piece set (lead, second, bottom) of M6 hand taps is going to be under £20 and a tap wrench for small sizes is about £10. To be honest, going into aluminium or soft steel you can probably get all your lifetime needs out of something cheap off of Amazon or ebay.