Please can you help us to choose the best value pass? Family of four, children aged 17 and 15. Arriving Gare du Nord Wednesday 2 August, leaving Gare du Nord Tuesday 8th August. We are staying near Porte de Versailles. We want to visit Versailles on one of the days. It looks like the Navigo Decouverte pass is not the best value? Thank you.
The best value pass or tickets is a question of how many one-way trips you'll make each day.
If you're thinking of making 4+ one way trips per day, an unlimited use (per-day) pass is better cost-wise. (We'll discuss which passes below.)
If making 3 or less one-way trips per day, single-use tickets are better cost-wise. (Convenience/peace-of-mind wise, multi-use passes are still better.)
So for Wed-Sunday which can be covered by a Navigo week pass, that's 5-days of coverage for all zones (including Versailles) for 30€ + 5€ for the card itself so 35€. To make 4 one-way trips per day for 5 days using single tickets for 5 days, that's 2.10€ x 4 x 5 = 42€. And I'm assuming you'd buy two booklets of 10, (16.90€ each) that becomes 33.80€ + 2€ for the Navigo Easy pass = 35.80€. Closer to a Navigo Week pass, but not better. If you make any transfers from Metro/RER to bus or Metro/RER to Tram using Navigo Easy and its preloaded tickets, those transfers are not covered by a single ticket so you'll be charged for 2 tickets. This would't happen with a Navigo week pass.
So for the Wed-Sunday I'd definitely suggest a Navigo week pass for everyone. (There's no children discounts for visitors, regardless of age.)
For Monday & Tuesday, if you're planning to make 4+ one-way trips, I'd suggest a Navigo Day pass 1-2 zone for each of those days (8.45€/day). This only covers central Paris and not Versailles, so making a visit to Versailles while the Navigo week pass is valid, would be optimal.
If you'd make less than 4 one-way trips per day on Monday and Tuesday, then single use Paris transit tickets without any sort of card is best.