I used to pay a particular company by purchase order for this exact reason. CC takes 2-3% of the payment, but purchase order - they've got to get themselves into the company system, track the PO, invoice, track the payment...at the time, a common estimate was $50 to process a PO, and if you're only buying $100 batches, that's a big hit. Did not like that company, but they were the only place to get whatever it was I had to buy.