Hi Emma, We just got finished our tour and had a fantastic time, with a super group and great tour leader.
You were asking about cash, first of all traveller's cheques are not a good idea - too difficult to cash. Wear a money belt. We used ATM's a couple of times as did others in the group. Only one English girl had a problem, but did find a machine that would accept her card. We found it easier and cheaper to use Egyptian pounds rather than US dollars - there are money exchange offices in most places.
Shopping is not too much fun. I have shopped and bargained at the bazaars in Asia, but found shopkeepers very aggresive in Egypt, and don't give you time to look at the merchandise before they start dragging out things you don't even want to buy.
Always have a couple of Egyptian pound in your pocket as if you have to use a washroom, you have to pay one pound for toilet paper.
Anyway, have a great time. The country is beautiful, the sights are many. Jean