Coupon is TESTANDCODE
I had already used it before realising it was one or the other, honestly its one of the better TLD’s IMO, too bad Cloudflare doesn’t support it yet.
Edit: I should have mentioned, you have to make a tentative payment of 1 USD, which is reverted.
If I remember correctly, I had to link my github account to get this, but I believe that was just for the free part.