Travel advice required (Vienna)

Dear Community,

I would like to visit Ljubliana (Slovenia) to meet a friend. However, it seems to be an almighty task trying to find reasonably priced travel options since flight prices are too expensive..Trains or buses are preferred options (also carpooling sounds attractive) .. are there direct ways to reach Ljubliana? Does anyone have a travel secret from previous experience? Looking forward to some enlightenment !

Regards
Aditya