How much money should I bring?
This is not easy to answer. If on a tour with the club my standard reply is $50 a day and that you have a credit card as back-up. You can use the credit card at a CADECA (bank) to get cash. You will be charged in USD at the exchange rate of the day. This will not be a great rate so keep to a minimum. Before leaving your home country inform your credit card company that you will be in Cuba, this will let them know the transaction is legitimate. It is very important to make sure your card is not from an American bank. A lot of Canadian Credit Union Credit Cards are connected to American banking systems and will not work here in Cuba
The exchange rates at the CADECA and at the bank are set daily by the Cuban government, there is very little difference between the exchange rates found at either the CADECA or the bank in Cuba. Therefore, there is no real point in spending the day shopping around for the best rate. I tend to use the CADECA more, as for me it is fast and fairly pain free and more conveniently located. However, make sure you get a receipt for each transaction, take your time before leaving the teller and check that the teller has given you the correct amount back, as they count the money really fast in front of you and I have been short changed in the past!
The CADECA in Cuba can also give you a cash advance on your credit card (credit cards accepted in Cuba). They usually charge a one-off transaction fee, you will then need to speak to your credit card company to see what interest charges they will apply on top of the transaction fee. One way to avoid accumulating interest charges is to put money onto your credit card, this way you can use it as a debit card.