Go to www.trenitalia.com, click on "english" at the top center, then enter your place of origin and destination, the date you want to travel (within 90 days of the date you try this), and the approximate time you want to leave. A list of the trains available will come up. Click on the little shopping cart beside the train you select, and another page comes up. It will ask you to select your fare (Flexi is the most flexible but the most expensive, Standard is as it suggests, and Amica gives you 20% off and can be purchased until midnight the day before the train leaves, if there are any Amica fares still left.) It will then show you the first and second class fares available for the fare category you have selected. If there is a "No" instead of a shopping cart, either you've gone too far into the future, or it's a regional train, tickets for which cannot be purchased over the internet.