The local currency is the Bajan dollar BBD, but US dollars are accepted in almost all shops and restaurants you will get your change back in BBD. The exchange rate is fixed at about 2 Bajan dollars to the US dollar. Keep in mind that exchangers in hotels and banks may take an additional percentage of the exchange typically 5%.
ATMs are widely available, although many banks ATMs charge up to 5 USD fee to withdraw cash using international cards. The only bank chain that does not seem to charge is the Republic Bank, which advertises its "Blue Machines" which are easy to spot.
Many "duty free" shops cater to visitors: from cruise ships. Bridgetown's main street hosts numerous jewellers, most frequently Colombian Emeralds and Diamonds International. Cave Shepherd department store offers a wide range of mercantile, while Harrison's offers premium gifts, leathers and cosmetics. Other smaller stores offer virtually everything a visitor or resident might need. A small mall at the harbour also offers decent prices and selection for rum and UK liquors, but goods produced in Barbados may be slightly more expensive there than elsewhere on the island.
Barbados has a well-deserved reputation for producing excellent rum, e.g., Mount Gay. Rum distilleries are usually open for tours, and typically offer samples and product for sale at prices often equal to the best found anywhere else. See also "Drink" below
Barbados has a great variety of street vendors. Haggle aggressively. Don't stop until you are at about a third of the original price.
The fine arts flourish in Barbados and many galleries and studios have shows on all year round which change every few weeks.
See also the note about "Weekend Shut Down" at the end of the "Eat" section below.
Stores selling to visitors can honestly claim they offer duty free pricing. They in fact pay duty on imported goods before offering them for sale. But as they sell anything to you as a visitor, they will ask you to sign a form that allows them to get a refund of the duty paid. The government is working on a law that allows vendors to obtain goods that are intended for visitors without paying duty.
In times past, most everything shut down on weekends, and visitors had to plan ahead especially if self-catering. This is no longer the case. Clothing and gift stores open until 4pm or so Sheraton Mall shops until 9:00pm on Saturdays; very few are open on Sunday. Many supermarkets island-wide are open on Saturday and Sunday.
Bank holidays such as Christmas, New Year's Day, Good Friday, Easter Sunday and Easter Monday will find most if not all stores and banks and business houses closed. But stores attached to gas stations will have limited availability of basic items, and shops at the deep water harbor will be open if cruise ships are visiting. There are a few small family run groceries across the island that will open on bank holidays or have a side door open to serve their community.