We know this area quite well (in fact, we will be back there in late April) but I cannot put an exact price on the train since we almost always have a rental car (about $110 for the day). But, getting to Eze is a bit of a challenge with the train since it only stops at Eze sur Mer down on the coast. You still need to get up to the village. There is a bus stop right in front of the little station, but the shuttle bus up to Eze runs on a pretty irregular schedule. If you can't get the bus, than you need to get a taxi (there is a cafe across the road where they can call you a taxi). There is a local bus line that runs between Eze and Monte Carlo (not sure of the bus number) and that is another option. I suspect that doing in on your own would cost at least $20 pp less than the tour, but it comes down to how much you like tours. One reason we like to do our own thing is that we prefer taking our time and eating lunch off the ship (hard to pass-up a good meal in France). Those half day tours waste too much time getting you to and from the ship so you can have lunch on the ship, and we have never figured out why anyone would go to places like France and Italy and than eat on the ship. We always smile politely when fellow passengers tell us they do not want to spend money on shore since they have already paid for their meals on the ship. Each to their own, but the culture of many countries (particularly France and Italy) can almost be defined by their cuisine. Nothing like some escargot to remind one of the slugs crawling on their sidewalks at home
Hank