It is better to bring cash to Turkmenistan. There are very few ATMs recognizing international cards such as Visa or Master Card. It is desirable to bring US dollars rather than Euro. You can exchange money at branches of banks (open Monday to Friday from 9:30 to 17:30), hotels and official exchange offices. The last mentioned ones will only accept "new" notes of the latest releases and series, no scuffs or inscriptions. There are also street money changers, and their rate is usually significantly more profitable to the official, but you can communicate with them only at your own risk. You can pay off with credit cards in a few prestigious hotels and restaurants in Ashgabat and in the offices of airlines but in the rest of the country only cash is accepted. Traveler's checks can be cashed in only a few banks, the dollar is preferred.