Can anyone suggest an unexpensive flight from HCMC to Siem Reap? I know VN air goes there but cost too much. There has to be more than 1 air carrier that goes there.

I do believe that is the only carrier. Flights in and out of Siem Reap from anywhere are expensive.

Kathie is right. VA is your only choice at the moment, although a new Cambodian carrier is supposed to start operations one of these days.

You could try Air Asia through KL or Jet Star Asia through Singapore, but I wouldn't expect you'd save that much money, plus you'd end up blowing a full day on a 30 minute flight. You might as well take the bus.

You could fly from SR to PP ($115, one hour) or take the bus from SR to PP ($12, 5 hours) then take the bus from Phnom Penh to HCMC ($12, 6 hours)

You'll blow a whole day this way, but it's the only way to save any $

There are 2 other airlines that will fly this route for the winter season.
Jetstar/Pacific starting Nov/01 with 1 daily flight at 10am is the cheapest. With carry on only $84, with 1 bag up to 20kg, $104

Siem Reap Airlines starts Oct/26 with 1 flight at 12.40. $150

Also you can take a direct bus. Mekong Express charge US$22 and Sapaco $20. Both leave around 7am and take around 10+hrs. These fares were last year and may have gone up by now.

Siem Reap Airways from Oct 26, see the other post, that informations 'should be' on Bangkok Airways website, that was in a press release, I have not looked on the website