but I suppose there is some kind of alternative discount programme especially dedicated to the region, that will work out cheaper for you than an interrail ticket.
Balkan Pass, buy at the Wasteels office in Budapest inside Keleti pu. train station.
You can find more info on the pass here:
And for finding out Eastern European rail prices go to www.jizdenka.cz
Leipzig to Prague
In Leipzig buy a Sachsen-Ticket Single and go to Dresden. Change money (get Czech Crowns) in Dresden. Take the S-Bahn down to the Czech border, Schöna, Bad Schandau, etc. See the sights there, then catch a local train across the border to Usti.
Prague to Vienna, Vienna to Bratislava, Bratislava to Budapest
Buy a train ticket to Bratislava in Usti. Use this ticket to go to Prague, break the trip in Prague. Go from Prague to Bratislava using the ticket you bought in Usti. From Bratislava take the local train to Vienna, the EUregio ticket is 14 EUR. Go from Vienna to Györ in Hungary, buy the ticket in Vienna. It is again a Euregio ticket for 14 EUR. Buy a local ticket in Györ to Budapest at the train station, paying with HUF.
[ Edit: Edited on 28-Jul-2009, at 00:50 by t_maia ]