They choose mail
The picker hands them a reference code and your mailing instructions. They put the payment and the code in an envelope.
Part of the economy still pays with envelopes, and "DM me and we will figure it out" serves it badly. Pay-by-mail gives those buyers a real checkout, with a reference code, an order status, and a clean record.
The picker hands them a reference code and your mailing instructions. They put the payment and the code in an envelope.
You match the code to the order in your dashboard, so there is no guessing which $40 belongs to whom.
The order's status flips, and the sale takes its place in the same log as every card and crypto sale.
The mail option accepts any unit you settle in, whether that is Goldbacks or anything else the two of you agree on, because you are the one opening the envelope. Price the product in your unit and the checkout speaks it.
An order that never arrives expires on its own after 30 days. That keeps your log a record of real sales and mail that is honestly still coming, not abandoned checkouts.
Mail is one option inside the same button, not a separate store. A buyer without a stamp simply pays by card or coin instead.
Pay-by-mail is included on every plan, even the free one.