Mullvad accepts XMR which is more difficult to trace than amazon related anything. Mullvad does however state that payment information is disassociated from account numbers 90 days after payment. Theoretically you could use any payment you like, pay the 90 day compliance tax, set a cal event, then begin using it about a week after that 90 days is up. Cheaper to use XMR.
The trick of selling via Amazon is that although Amazon (and thus the government, if they subpoena'd that info) could easily see you're using Mullvad, they could not figure out which Mullvad account was yours.
