The Cuban money you used in the past--the CUC--is now gone but Canadian, UK, EU and other currencies can be exchanged at a bank, or at a CADECA for the Cuban Peso--CUP.
The value of the Cuban Peso is pegged against the US Dollar.
US cash is no longer accepted in Cuba and cannot be used anywhere. You are welcome to bring US dollars, but they will only be good on the Black Market.
You will receive 124 pesos to the US Dollar at official currency exchanges. However, the Black Market exchange rate is currently 200 pesos to the US Dollar. You decide.
Do not attempt to bring any of the old Cuban currency known as the CUC into Cuba. It is forbidden to do so since this money has been withdrawn from circulation.
Where to Change Your Currency
You can change your foreign currency at
your hotel, at a Cadeca or at a bank. They will give you Cuban
Pesos, which is now the only accepted currency in Cuba.
Better quality food and goods are found
in the MLC shops. To buy these goods you must use a credit card--one which is not issued by a US bank.
The shops are now known as MLC stores which means "moneda libramente convertible" or "freely convertible currency".
This is now the only way you can buy goods in the former CUC stores, which are now known in Cuba as MLC stores. You cannot use actual cash--neither pesos nor US dollars or any other currency--in these stores.
If you exchange some of your currency for Cuban Pesos, you can use it for taxis, in restaurants, to buy street food or peso shop items. Owners of private paladares and private rentals prefer to be paid in US Dollars.
If you have a credit card issued by a US bank--leave it at home
American Express is reviewing the new regulations regarding use of American credit cards in Cuba. They hope to soon allow customers this choice.
People should contact their bank before traveling to ensure that their card will be supported there.