Sweetwater offers Native Instruments Komplete 15 Select Bundle for FREE (US only)
https://www.sweetwater.com/software/komplete-15-select

It says US only, but you can just use Fake Name Generator and it will work.

You can use three different email addresses to get all three codes. However, it seems that each NI account can only redeem a maximum of two discount codes.

You can get ALL THREE by using 2 NI accounts, then activate the serial keys on just one account in Native Access.