There are different busses from Luang Prabang to Vien Vieng. The price range is between 110.000 and 180.000 ($13.5 / $22)
We took the bus at 17.00 from the north busstation in Luang Prabang it was a normal seats bus and the ride seposed to be 6 hours. The road is quite bumpy and the ride took us 9 hours. When you’ve the choice go for the seats on the right probably you can see the sunset over the mountains. When it is dark the view on the stars is amazing, because there are almost no lights you can see them very well! We arrived at 1.45 in Vien Vieng.
Or book your bus easily online by Bookaway.
At the bus stop they offert us a room for 100.000 ($12) for 3 persons so that was great. The room was good.
Tip: Next time i’ll take the night/ sleeperbus. So you save a night and money for the hotel/ hostel.
Time for a beer and a sleep now!