What is the most economical transport card for unlimited use for 3 or 4 days (starting from Saturday), including the train/bus from Charles de Gaulle Airport airport to the city.
Your options are:
- Point-to-point tickets. For transportation inside the Paris city limits (where most tourist attractions are, but not the airports, Versailles or Disneyland), buy 10 tickets t+ for €14.90. From Roissy CDG airport, a train ticket (cheapest reasonable option) costs €10.30. To visit Versailles, 2 tickets (there and back) cost €7.30. Children under 10 pay half price, children under 4 travel free.
- Day pass (Mobilis). The cost is €7.50 inside Paris, €12.40 valid to Versailles, €17.80 valid to Roissy CDG airport. It's rarely worth it.
- Weekly pass for €27.90 (valid for the whole region, including a one-time €5 fee to get the pass itself). These are priced for commuters so they're a lot cheaper, but a week runs from Monday to Sunday, and you can only buy one for the current week until Thursday night.
- Paris Visite. It's usually more expensive than other options (53.75€ for 3 days, 65.80€).
So in your case, point-to-point tickets are likely the cheapest option.