This morning I was looking on-line for for a rather obscure book. Found it used via Amazon for $80.00. That was much than I wanted to pay, so I kept on looking. I soon found it at a small specialized store out east, for $29.95. This place has no online ordering system, and does not take credit cards. Their ordering page simply says:

At present I don’t have a capability to accept credit cards as payment for orders. To make it as convenient as possible for my customers, I will send you your orders with an invoice for the amount due. When you receive the books that you ordered, please send me your check as soon as possible.

This practice has worked very well for over ten years now with the vast majority of my customers paying promptly. Let’s hope that this arrangement continues to be practicable.