Do you mean what kind of railpass? A train ticket is just that — a ticket that allows you to take a train from point A to point B. It can be a general ticket, good on any train on that route, or a ticket with reservation which would be good on a specific train (date and time). Some trains require reservations, so if you have a general ticket you’ll have to buy a reservation to take a train that requires one.

A railpass would serve as your ticket for just about any train you take within the limits (time range and countries covered) of your pass. Reservations are extra. Which, if any, railpass to buy is a difficult question. If you have a very exact itinerary (down to the specific dates and times you want to take) you can look up the cost of each ticket and see what specials are available on the individual national rail company websites and then buy those tickets in advance. This will take hours of planning time and require you to buy non-refundable tickets several weeks in advance. Another option is to use railsaver — which the trip planner here has already done for you! Pasted from your eurotrip:

I’d use the recommendation. You’d buy cheap point to point tickets for your trains in Poland and Czech Republic. How are you planning to cross the channel? I’d go for Eurostasr, the chunnel train as it’s much faster and more convenient than flying. Look for specials on the days you want to travel at www.eurostar.com

yeah, I meant a railpass haha

Thanks for the info, and you mean the English Channel? If yes, then yeah, I was planning on going by train. Is the chunnel train more expensive then regular trains? If so, how much more roughly?

Eurostar uses a pricing structure like an airline. Cheap tickets are often available for non-peak times like the middle of the day during the middle of the week. Prices vary widely.
Use www.eurostar.com to see what’s available when you want to travel.