I am looking at rail prices from Prague to Kosice Sl
For the same day for first class the Czech railroad web site has the price at $40, CZECH transport $82 and Rail Europe $212. All are in USD same day time.
How can this be?
It is widely reported here that RailEurope sometimes has large mark-ups on the tickets it sells and that it does not offer all the possible trains (perhaps only the most expensive ones??). So maybe part of the difference is that you are looking at two different departures?
The usual advice on this forum is not to buy tickets from RailEurope.
It surprises me that the difference is that great, but this is an example where I would not buy from Rail Europe. They don't have any direct agreements with the eastern European railways, so their tickets have to come through a western-European middleman that marks up the ticket prices, and exchanges the currency more than once, as well as they don't have access to advance-purchase discounts (if any).
I would expect you to pay closer to the $82 rate on the spot in Prague. If you're ready to book now through the Czech site, then try it, especially if they sell the early-morning direct trains; they probably can't sell connecting trains.
If you are not taking an overnight train, then be sure to look out the window because it goes through a pretty spectacular part of Slovakia (properly abbreviated as SK). Actually, its a long trip and if it were me I would get off at Poprad (about half way) and spend a night at the Grand Hotel Kempinski High Tatras. Amazing hotel in the middle of stunning scenery and near some pretty decent fly fishing.....
Go to http://www.idos.cz . You will find out that three companies serve the direct connection Praha - Kosice: Ceske drahy (CD), Regiojet and Leo Express. For second class (which is pretty good) you will pay between 369 to 497 Kc (crowns) = US$ 14.50 to 19.50. First class is usually 50% more. The fastest train is Pendolino (CD), it takes 7 hours 22 minutes. James has very good recommendation. Hotel Kempinski (while relatively expensive) is one of the best hotels I have ever stayed in with absolutely stunning views. It is in Strbske Pleso. To get there faster don't get off in Poprad but in Strba (one station before Poprad).