Vietnam Airlines from Singapore to Phnom Penh has 6 flights every day. And there are 42 flights per week flying out of Singapore which connect to Phnom Penh.
The price for economy class – one way ticket of Vietnam Airlines from Singapore to Phnom Penh is 5.798.000 VND (or ~$288 USD) and the price for bussiness class – one way ticket of Vietnam Airline is 7.553.000 VND (or ~$376 USD).