You can also get a Venice Card, which has various options that you can choose when you buy it (public transportation, cultural attractions, toilet access, Alilaguna, etc.) There is a 'Junior' version of the Venice that is available at a slightly reduced rate for those between 5 and 29 years of age. Note, however, that a Venice Card is not recommended for those with less than 3 days in Venice, as most of the top attractions are not included in the Venice Card. If you'll be staying in Venice for a week - get the Venice Card and enjoy travelling from island to island and exploring the various museums and churches it offers access to.