UPDATE - all information is listed here: rail.cc/en/interrail-train-reservation
All the high speed train costs depend on the distance you want to travel
Night trains with couchette: Cost according to distance but cheaper in the East: e.g. Basel to Berlin €20: Krakow to Prague €12. Roma to Nice €35
Without couchette around €3 - €5.
Watch out: Trainhotels are much more expensive.
Have a great trip.
I'll in interrail trip next week and still have a lot of doubts about price of supplements in specials trains. I'd search in railcc and another sites and didn't find the same price in many sites. I did a list of trains taht I need help and I expect that someone can help me.
:arrow: Paris to Bruxels
:arrow: Malmo to Oslo
:arrow: Wien to Venice
:arrow: Rome to Nice
PS: Sorry about my poor English but I promess that your any doubt about Portugal I'm ready to asnwer.
Thanks guys and sorry my long post but I need ops: