One tricky thing that happened to a group of us is that we were buying things on the street in Aswan. And my friend gave a 50 pound note and it was kind of chaotic but the vendor gave back the note and said this is a 50 cent (half pound) note and it wasn't enough to buy what we wanted. Both the bills have a giant 50 on it so unless you were paying close attention, the vendor either is right, or he switched it on you and when you gave your 50 pound note, he did the old switcheroo and said you gave him the half pound that also has a 50. Pay attention as there is a big difference between 50 pounds and a half pound. Like $50 dollars or 50 cents! And my friend couldn't be sure what was given, but thinks he was ripped off.