You shouldn't have any trouble with US dollars.

Debbie, the only thing I'll caution you on is they are very aggressive sellers...the best in the world. I made the mistake in the "Casbah" of being too polite, looking them in the eye and saying something like "No Thank You". Well to them this just meant, maybe I didn't want the item in pink so the next thing I had a yellow, a blue a whatever, shoved in my face. Be careful not to make eye contact....that is a real buying sign to them! Just keep walking and looking straight ahead and you won't be swarmed like I was.

It is an amazing place that everyone should visit at least once!