Hi! Today night I'm going to flight to Tunisia. Yupie!

I going to stayat thehotel in Sousse. I'd like to travel in Tunisia and I wonder what's the cheapest form of traveling: bus, car, train, taxi? I'd like to travel by myself because I think that trips organised by hotel are more expensive, ist't it?
P.S. Where can I change Euro for Dinar? Is it possible in Sousse or I have to do it in airport???
Have a nice day!