If you would like to stay in a sleeper car, that also requires a reservation. Trains do leave on time so make sure you are on the platform ready to go. There are many options for low-cost accommodations in Europe, but realize that you won't be staying in a palace. One of the best options for low-cost accommodations is the hostel system. The card also offers the perk of being able to reserve space up to six months in advance.
Hostels offer a very social atmosphere and the chance to meet new people from all over.
I flew from Madrid to Zurich, Switzerland and I was traveling alone for the first time. Although no specific type of building defines hostels, they can be old apartment complex buildings, old school buildings or old rooming houses. The type of room ranges from large rooms with a lot of bunk beds to private rooms. Summer is the peak season, so it is a good idea to call ahead or arrive in the afternoon to look for somewhere to stay. Some hostels also provide excursion possibilities, laundry facilities and kitchen access.