PARISPASS.com?

I don't want to sound judgemental, but its the worst value around. Buy the PARIS MUSEUM PASS separately.
For getting around Paris, you could also buy the Visite separately as well, although most people here even consider that a poor value. You can buy a pack of 10 Metro tickets (called a Carnet) for 14 euro and change.
You will never be able to make your money back on the package of discounts included in the Paris Pass. Skip it.

Be aware that there is a Paris Pass, a Paris Visite Pass, and a Paris Museum Pass. They are different, and yes, it is confusing.

The Paris Museum Pass can be a good deal, particularly if you are going back to big museums like the Louvre multiple times on your covered days (or, in my case, if you climb the Arc de Triomphe twice, once during the day and once at night). The other two are usually not good deals for most visitors. They will dangle a long list of covered attractions, but there are only 24 hours in a day - how much can you see in that time?

For transit, the passes that cover it are for outer zones that most visitors only go into for the airports or Versailles (or Paris Disneyland). So, you're paying extra for zones you won't use, or only use once each. Instead, if you're staying 5 or more days in a Monday to Sunday period, get a Pass Navigo Decouverte. If you're not, get a carnet of regular metro tickets (10 tickets sold at a discount). For Versailles or the airports, buy separate tickets specifically for these (you can't use a regular metro ticket for these destinations; you will be able to get on in Paris, but won't be able to get out the automated gates at the other end).

Harold, thanks for the info about the carnet of metro tix. Would hate to not be able to get out at Versailles!

And it isnt the 'getting out' that is the biggest problem; if you are caught without a valid ticket the fine is enormous and on the spot. This is true in the metro as well; if you cannot produce a valid ticket for that trip you are fined on the spot. The check on the trains outside Paris like to Versailles or Fontainebleau are frequent although not ever single trip. The checks on the metro are infrequent but I'd say we average about one check a week in Paris. So hang on to your validated ticket before you leave the system.

piling on

The Parispass is a waste of money for almost everybody.

The Paris Visite is unlikely to save money.

The Paris Museum Pass saves most people both money and time.

Do the responses about PARISPASS hold true if we are staying at a timeshare at EuroDisney and planning to travel into Paris each day for 6 days? We understand that is in Zone 5. Is there a single, affordable travel pass that we can purchase to go in and out of Paris and travel around in the city while we are there each day?
Does it still make economic sense to buy separate Museum Pass?

The Disney conversation is continued at https://community.ricksteves.com/travel-forum/france/staying-near-eurodisney-with-daily-trips-to-paris.

Yes, Because the PARISPASS is simply a bundle of A, B, C, D, E, F, G, H, J, K, and L. You only want A and B, so why pay X for the whole bundle when you can get what you want, A & B for 1/2 of X. The 5 day all zone Visite is not the worst deal, buy it if you want from any transport ticket window.

Or to clarify further, the Paris Pass sounds to those unfamiliar with it that it is a Pass -- a pass that gives you travel and museums and such BUT it is not 'a pass' if by that you mean a single card that does these things. It is a commercial marketing gimmick which takes the ordinary Paris Visite travel pass (the same one the public transport system sells to tourists and which is overpriced for most) and throws it in an envelop with an ordinary Museum Pass and adds some coupons.

The Paris Visite is normally a bad deal. If you are commuting to and from Paris every day from zone 5 and you are not there between Monday and Sunday of a single week then it might be worth getting. If your trip is mostly between Monday and Sunday of a single week, get the Navigo Decouverte.

Ditto to all of the above about the Paris Pass: I've no idea how anyone breaks even on that one. I did do the math on the Paris MUSEUM Pass, and that one worked really well for us. Like any other pass, though, you have to have the time and the interest in the attractions it covers to get the good of it.