I don't know if they accept credit cardsetc., but I found the Paris Visit card to be perfect. You can buy it at the airport, for 1, 3 or 5 day stays for up tp 6 zones, depending on where you will be travelling. I bought the 5 day zone, 1 -6 card (which includes the airport run) for about E43. I was on the Metro alot and used it for Versailles also. You also get discounts off some tourist spots if you show the card.