Vietnam Airlines from Singapore to Vientiane has 3 flights every day. And there are 21 flights per week flying out of Singapore which connect to Vientiane.
The price for economy class – one way ticket of Vietnam Airlines from Singapore to Vientiane is 6.773.000 VND (or ~$337 USD) and the price for bussiness class – one way ticket of Vietnam Airline is 10.283.000 VND (or ~$512 USD).