A cheap and typical way to move around PP is by these bycicles. They cost slightly more than a moto ride, but are far more charming, as you go real slowly among the incredibly thick city traffic. As you go in front, you can feel a little "vertigo" when motos and cars cross in front of you, but don't worry, I didn't see any crash (that doesn't mean there aren't though...).
And if you are worried about "the poor old man cycling for you", think that he would have to work much harder to earn the same in other job here...
It's amazing how hard they can cycle, sometimes carrying 2 or 3 persons in the same cyclo.
This is one method of transportation I don't really recommend. You sit on a seat at the front of a tricycle and proceed along at a very slow pace. I certainly felt very exposed out front and even more so when we came to a crosssroad where we had to cross a much busier street(ie. Monivong Boulevard one of Phnom Penh's main roads). Did we stop? Barely - and that was only because a truck was almost on top of us. Basically we wove our way through the cross traffic hoping they would either swerve or slow down. Of course all the local traffic is used to this and we got across ok.
I did not take one on this trip, but one of they make an offer to me, USD 1.
U can get it anyway, there is a lot around.