Checks are not accepted to purchase money orders. Credit cards may NOT be used to purchase money orders.Pay for the money order using cash, debit card, or a traveler's check. Locations like the USPS won't let you pay for a money order with a check or credit card. You can typically pay for money orders using cash or a debit card. Can I buy a money order with a credit card? Most providers do not accept credit cards for money order purchases and, if they do, the credit card issuer will typically treat it as a cash advance. You typically can't buy a money order with a credit card. Instead, you'll need to use cash or a debit card that takes funds directly from your bank account. To fill out a money order you need to first fill out the who the payee is, the purchasers information and sign it.