Martinique is a dependent territory of France and uses the euro as currency. US dollars are not accepted in shops, but some stores and many restaurants and hotels take credit cards. The best exchange rates can be had at banks. Not all banks will do foreign exchanges and may direct you to Fort De France to do such transactions.
Reportedly, the best offerings include French luxury imports e.g., perfumes, fashions, wines and items made on the island, e.g., spices and rum. And some merchants offer 20 percent tax refunds for purchases made by credit card or travelers' checks, though many may not accept the latter.
Shopping opportunities include:
Galleria, in Lamentin near airport, is the island's largest mall, with several European branded stores and others.
Fort-de-France's Spice Market offers stalls full of local/unique flowers, fresh fruit and vegetables, and herbs and spices.
Rue Victor Hugo...Fort-de-France's main shopping street...a strip of sometimes tiny, Paris-like boutiques, island shops and vendors of fresh fruit and flowers
As a decidedly Catholic island, very few stores are open on Sundays or holidays celebrated in France.
Business hours: Sundays may find many stores closed. Check in-advance before hiring transport to any particular store or shopping area.