I suspect that depends on where in the world. In Sweden, the classic "order by post" required paying at the post office as you picked your parcel up, with only

I suspect that depends on where in the world. In Sweden, the classic "order by post" required paying at the post office as you picked your parcel up, with only the pick-up slip (with the total to pay) being delivered to the address. I have seen a few Swedish companies who didn't use the Swedish postal order system, instead opting to send a package with a giro slip and an "pay within X days" inside. My understanding is that the post office took a small cut of the postal order payment, as a fee for guaranteeing payment. And the companies instead sending a giro slip had enough compliance with paying that it netted more money.