Letters and postcards sent to Europe and the US take about a month to arrive. While sellos (stamps) are sold in Cuban pesos and convertibles, correspondence bearing the latter has a better chance of arriving. Postcards cost CUC$0.65 to all countries. Letters cost CUC$0.65 to the Americas, CUC$0.75 to Europe and CUC$0.85 to all other countries. Prepaid postcards, including international postage, are available at most hotel shops and post offices and are the surest bet for successful delivery. For important mail, you're better off using DHL, which is located in all the major cities; it costs CUC$55 for a 900g letter pack to Australia, or CUC$50 to Europe.