After having just visited, here are some of my tips:
1) when you arrive at the airport, the first Foreign Currency Exchange place you see has poor rates, if the other places inside the airport are open use them, e.g. Post Maroc has good rates. The airport has an ATM which you can use also. In the Jemma El Fna square, Hotel Ali has good rates, and also banks. Small local places have good rates also.
2) If shopping, check out a few places to compare prices, play one vendor against the other to see who offers the best price, and aim to pay 1/3 to 1/2 of what they initially ask for. You can always buy your items in the last day or two. Do not be afraid to haggle!
3) If buying Saffron, the cheapest place we found (40MAD per gram, good quality) was close to Saadian Tombs (to find: go to Case Saada opposite, its round the corner from it on its left, up a laneway).
One litre of good quality olive oil was 45MAD at the north end of the square to the right, across from Cafe de France, around the corner from Les Terrasses de l'Alhambra restaurant to the left, you will see a couple of sellers. You can taste before you buy.
You can get a 2MAD ice cream just off the square, just past Patisserie des Princes, great on a hot day.
4) We found haggling taxi fares annoying, so we used the local bus. Its only 4MAD each, just ask the bus driver what number bus it is for the place you want to go, e.g. Jardin Majorelle is no. 15 bus. Buses do not go everywhere however, and they are busy at peak times. Catch them near the square.
For petit taxis (max of 3 people) a good price is about 4MAD each person, and grand taxis (4+ people) its about 6MAD each. If you pay round about that, its fine.
5) I got an INWI sim (Tic-Tac callplan), there are stores in a few places e.g. one at the airport, for 30MAD, then topped it up for unlimited internet for 7 days for another 70MAD. You can make a few calls and texts too as they give you 20MAD some credit to begin with. Reception was fine, and internet speed was reasonable in marrakech and essaouria. The INWI place will set it up for you.
6) If going to Essaouria, you can ask your Riad to get you bus tickets 1-2 days in advance, 70MAD one way, takes about 3hrs, and you can browse the net on your phone as reception is good all the way. You then buy your return ticket in Essaouria. When you arrive, its only 2mins walk to the medina gate, follow the people as they know where to go. If you have GPS on your phone you can use that to find your way around, its not big.
7) If eating at the night food stalls in the square, try and sit in the middle of the tables as you will get less hassle from sellers/beggars etc who walk around the outskirts sometimes.
8) You should definitely try Tangia (local meat dish, eaten with bread and cumin), on the square, go to Les Terrasses de l'Alhambra, round the corner from it to the left, there are a couple of places, the first one was busy and good, only 60MAD for 1/2kg, 120MAD for 1kg.
9) I highly recommend the TripAdvisor offline city guides app.
10) Get your Riad to arrange pickup from the airport if possible. Makes things easier.
11) Try and always have small change, coins etc. It's handy, and in case vendors/taxis give you the ole "no change" line.Edited: 2:20 pm, March 22, 2013