If you prefer to go to Monaco as part of a youth group, you should take a lot of money with you. There are about 15 hotels on the territory of the country and all of them are of a very high class with corresponding prices. You can save a lot of money if you find accommodation outside Monaco.
In terms of leisure activities, young people tend to come to Monaco to watch the Formula 1 Grand Prix. To save money on tickets, book in advance. tripmydream can help.
If you prefer a sightseeing vacation in Monaco, then you can visit the Oceanographic Museum. There's a huge collection of all kinds of sea creatures, shark and whale skeletons, as well as marine equipment, ships and artifacts from maritime expeditions.
A beach vacation with a rowdy group of young people is possible in Lervotto. This place attracts attention because there are not only paid but also free beaches, toilets, and changing cabins. The well-developed infrastructure will not let you get bored for a second.