Credit card

Credit cards seem to work most of the time in KSA but are sometimes unreliable.
Amex is accepted fewer places than Visa/MC here.
Some places, generally smaller stores, will add a 2-3% mark-up if you use a credit card.

I have a card issued by NCB in KSA which is the most reliable one here.

There are a couple of US-issued cards which have no foreign transaction fees - Capital One Venture Card (no annual fee) and British Airways Visa Signature Card ($95 fee).

If you travel on business from Aramco they will refund you the annual fee for one credit card. You have to submit the statement showing the annual fee with your expense claim on your next business trip.