[insidious]

Also, you can pay with BTC or cash is you want to have no ties to your account.

If you want your anonymity Intact, cash (where applicable) Is the best way to pay for the service. You'd want no links whatsoever to any entity relative to your Identity.

I agree with mothered, i've used PIA as my goto VPN for a few years now and it's been great. You also have the option of paying with GiftCards, which may not be as anonymous as Bitcoin perse but still a valid option