[winkelmann]

> if you don't mind buying grey market keys

Please don't buy "grey market" MS keys (i.e. super cheap keys or keys for products not sold to end users, like LTSC).

Either buy keys from legitimate vendors or use alternative activation methods (emulated KMS, etc.). I believe a lot of these grey market keys come either from MSDN subscriptions or leaked MAK keys, in either case, you aren't really paying for the product, you're just funneling money to sketchy people.