What do the train tickets cost?

That depends on the departure and arrival station, the comfort level and whether it is expected to be busy. The ticket prices per comfort level and allocation can be found on The Good Night Train to | European Sleeper 

• For a bike, you pay 19 euros and travelling with a dog or cat is free so long as you book a private compartment.
• Children aged 4 to 11 always pay the cheaper Easy Night fare, subject to the conditions of the Flex Night fare.
• Children aged 3 and under travel free if they share a bed, couchette or seat with a paying passenger. A bed, couchette or seat may only be shared by one child aged three and under and one other person. If you would prefer your child to have their own bed, couchette or seat, please book a ticket with the child fare.