I know you asked about train tickets; however, perhaps you may be interested in checking out the bus that goes from Dresden Hauptbahnhof - main railway station - to Prague. I have to dig out my Dresden info to find the particulars. I think it is called Europabus. Dresden, by the way, will send a package of tourist info free via air mail in English (and several other languages)if you request it via e-mail on their web site. I'm considering the bus for my upcoming trip, I think it would be more scenic than the train. I believe the price was around 28 Euro for a one-way ticket. This busline goes all over Europe and also has a route from Prague to Munich. I'm sorry I don't have more detailed info but my trip is months away and I haven't done any specific planning yet. My Dresden info packet is from last year.