I'm taking a night train from Prague to Budapest. I've heard with the couchette you will share your sleeping area with 4-6 people. With a sleeper, do you have your own compartment(i'm traveling with a companion) ? What's the cost difference between a sleeper vs. couchette ?
Depends on the train and what fares you can get for that train.
The compartment is a bit more, but the privacy... worth it!
Try Euraide's website. Under 'Current EurAide Info', it will give you an idea of the costs of different sleeping options. These are European prices though; you will pay more if you go through an American agent.