Roma Pass worth the money?

If you expect that you will visit at least two of the museums and/or archaeological sites listed here, and will make use of Rome transit (Metro, trams, buses, Lido line train to Ostia) a few times or more over a three-day period, then yes. If you don't intend to use public transit more than once or twice, then it probably doesn't pencil out.

The youngster won't need a Roma Pass regardless, because his entry to the sites will be free. Just buy a transit pass for him.

Plan your use of the Roma Pass so that your two free entries will be at the most expensive sites. Last month, when my grandson and I were in Rome, we stopped at Ara Pacis, thinking I would use my second "freebie" there. The nice man at the ticket desk asked us what other sites we planned to visit. We told him we were going to Ostia Antica the next day. He suggested we could save money by paying full entry price at Ara Pacis, and using the Roma Pass to get into Ostia free. He was right.

No need to buy the Roma Pass online. You can buy it at TI's, transit stations and newsstands all over town.

More information available here.

You can also buy it at the first site you visit. Note that it's a 3-day pass, not 72 hours. (There may be a 2-day pass as well.)

There is a 3 day pass (not 72 hours) and a 24 hour pass (not 2 days). These are both different and have different rules so read up on them to see if one is a fit for you. You'll need to do the math to see if either will be of benefit based on the sites you plan to visit.

The 10 year old won't need a pass.

Donna

When we were in Rome in May of 2014 my wife an I got the Roma Pass. I am sure we at least broke even on the museum/historic site entrance costs but the big advantage was being able to use public transit without purchasing additional tickets. You just walked on.