Can I use an American Express card to buy a STEPCRAFT CNC?

Yes you can, but you need to select PAYPAL at checkout and then when you get to the PayPal page, there is a link at the bottom of the page to pay with your Credit Card.  You do NOT have to log-in to a paypal account to use Paypal as a card processor this way.

You should be able to use Visa, Mastercard, AMEX and Discover.