One option is to use PayPal Here (assuming you have a business account), you can either accept the card payment in person or do a "no card present" manual entry. Note, there's no buyer or seller protection with PayPal Here, see User Agreement details. If you do a manual no card present entry, there is a higher transaction processing fee (3.5% + $0.15 per transaction) and there may be a delay with receiving funds.
Another option is Virtual Terminal - there's a $30 monthly fee plus the standard transaction processing fees.
