Great sale fare$45one-way
Typical low fare$60–$90one-way
Which airlines fly it cheapest
Thai AirAsia.
The local trick
💡 Consider Bangkok → Siem Reap (Angkor) overland, then bus to Phnom Penh ($10).
Corridor intel — Within Southeast Asia
AirAsia, VietJet, Scoot, Cebu Pacific and Lion Air keep intra-SEA fares tiny — but bag fees can double a $30 fare, so pack carry-on. For trips under ~500 km, buses and trains (book on 12Go) are often cheaper, comfier and station-to-station.