What is the best way(cost & time)of transportation between Prague, Czech Republic and Ljubljana, Solvenia?
I couldn't find any cheap flights between the two cities on www.whichbudget.com. For the train, it's a 12.0hr.-16.0hr journey depending on which run you choose. The fare would be about $200.
If you're planning to make a round trip, try Czech airlines. Depending on the day you travel, it can be as low as $400 RT. Unfortunately, as Larry notes, no sign of discount carriers making that run.
Laibach (Ljubl...) isn't that far from Trieste which you can fly to from Prague on SkyEurope. www.skyeurope.com