Check Railsaver.com and the national rail sites pinned @ top of this forum.

1. Thalys is the “brand name” for a specific set of high speed, luxury express trains connecting Paris, Amsterdam, Koln and Brussels (and maybe a few others). If you take the train, you will probably be on a Thalys train between Brussels and Paris and perhaps for a few of your other legs.
2. Cheapest is probably bus, but it’s usually enough slower that I don’t think it’s a reasonable option for this trip.
3. Railsaver, as Don recommends, is built into the trip planner. It recommends a 15 consecutive day global pass for your trip. This is probably the cheapest option, but you might be able to beat it buying special low fare tickets on-line from the individual national rail company websites. The links are in the sticky Don mentions, or under “transportation” on the “travel tips” tab.
4. Check schedules for your trip on the German national rail company website: http://reiseauskunft… I think you will find this trip is way, way too rushed for 13 days. If your 13 days includes travel time to/from Jakarta then cut to 4 cities. If 13 days doesn’t include those flights then you can add a 5th city. The trip planner will probably recommend a select pass or a flexi pass if you put in a more reasonable itinerary.

Shop around on Thalys-operated train segments. Momondo.com sometimes turns up the same trains for less if you book it from the Dutch rail site instead of French or Belgian, for example. Enter it like a “flight” on Momondo.com and if train is an option on that route, it should show you train fares among flights, and the source for booking it for whoever has it cheapest. Of course this means you book ahead and are locked in — use it or lose it. With a rail pass, you have much more flexibility.

thank you guys for all the informations. for now i couldnt find the train fares at least until May. i think Railsaver is more expensive for this budget traveller.

Most of the national rail companies only sell tickets 60, or sometimes 90, days in advance. However, prices seldom change, so you can get an idea of what’s available for specials. Remember that you might not be able to actually buy tickets on-line for the special fares, which means some sort of rail pass may save you money. I doubt that the 15 day global pass will be the best deal once you rework your itinerary to something more reasonable.