The West African CFA franc XOF is used by Guinea-Bissau and is also used by its neighbours, Benin, Burkina Faso, Côte d'Ivoire, Mali, Niger, Senegal and Togo. Strictly speaking, it's a separate currency from the Central African CFA franc XAF with the bank notes being different, but the two currencies are used interchangeably one-for-one throughout.
Both these CFA franc currencies are guaranteed by the state and pegged to the euro at a rate of €1 = 655.957 CFA francs.
In December 2007 the first ATM's arrived to the country of Guinea-Bissau - in the BAO Banco da Africa Occidental branches of Bissau and Gabú. An ATM is also being set up in the Hotel Malaika in Bissau. These ATM's only function if you have a local account with that bank. So, leave your credit card/bank card at home because it will do you no good. Probably still safest to bring euros or francs CFA enough to cover the time you plan to stay. Western Union is present in Bissau eight locations, Bafatá, Gabú, Buba, Canchungo and Mansoa. They will rip you off by taking 10%.
The largest market in the country is Bandim Market, which is on the main road going into town. You can buy many things there and the atmosphere is nice. Otherwise there are small vendors on most roads of the capital. In the villages Tabankas you will also find small vendors selling the necessities. In the main towns in the countryside there are larger markets called "Lumo", which give farmers and merchants the possibility to sell/trade their goods. Don't forget that Guinea-Bissau is a poor country and as such the possibilities for shopping are smaller than in the Gambia or Senegal.
When shopping in Guinea Bissau you have to keep in mind that locals quite rightly tend to consider foreigners as rich especially white people. The first price you are asked to pay will always be much higher than the actual price of an item. Haggling is absolutely common and no item should be bought without haggling for a better price.
Useful creole shopping phrases:Ke ku bu misti? what do you want?N'mistil I want itN'ka mistil I don't want itEs i kanto How much is thisRapatil Request to lower the prize
More phrases at Creole phrasebook