Ok, there do exist actual gas stations in Cambodia, even one or two in the small town of Kep itself, but for motorbikes and scooters, this is usually it.
In many parts of southeast Asia, particularly anything right outside of town, what you’re most likely to find when you go searching for gas is a cart at the side of the road with old whiskey bottles filled with yellow (regular) gasoline.
If you’re lucky you’ll stumble upon some bottles with red liquid – that’s the recommended stuff and goes for 5,000 riel per liter, about $1.25 US.
And then sometimes you’ll find a barrel with a hand pump, like above. A hand turn pump pulls the gasoline from the barrel into the clear holding container on top, and the hose brings it down into the bike. Measurement lines on the container clearly distinguish the liters so you can physically see how much gasoline is put into your tank.