Ask yourself: what do you want to versus need to protect and why? Privacy for the sake of privacy is a waste of time, energy and other material, physical and mental resources. Formulate your threat model by spending some time with a pen and paper, answering the above question.

With that out of the way: I buy vouchers, because there is a physical retailer in my country that sells them and they are thankfully not hardcore affiliated with big tech yet. Previously, I used to pay with credit card, since PII is not saved it their payment tokens and even the tokens get deleted after six months, I believe it was.

If you need anonymity and you need to leave no trace of you having purchased Mullvad, use cash. Don't forget to put on vinyl gloves. Withdraw a vastly different amount of money from the ATM than the cost of the subscription fee in question. Deposit the envelope at a postal office - or box - not in your neighborhood.

Edit: I just recalled, that I did try paying with cash once. Worked like a charm. Naturally, there was a delay.

Define "worth it." I think Mullvad is a tad expensive but for protection while surfing the web it's a good service. And the fact that they take mail-in cash is unique.

You can just look for a pre-paid credit card wherever you are. You may have to sacrifice your name and number but you don't have to wrestle with the post office.

Monero fixes this.

Just use monero.

The costs of shipping cash are: $1 or less for a security envelope, $1 or $2 for an international stamp (unless you live in Switzerland in which case it’s less). I usually just use the pen and paper I already have around or scavenge some scrap to write on.

I get the one time code from the mullvad website, write it on a piece of paper, put it and my payment in the envelope, write the address (no return address), apply the stamp, put it in some mailbox and wait for it to hit my account.

It’s often more than two weeks because they don’t process cash and mail every day. That doesn’t bother me because I keep an eye on the months left and re-up with plenty of time left.

Is it worth it? I tend to put more trust in the anonymity of easily broken chain of cash transaction than in the immutable ledger of cryptocurrency technologies.

Crypto is an option. https://digitalgoods.proxysto.re/en accepts many payment methods if you want to buy from them.

I went with a voucher from the big A and had it sent to one of their lockers.