I was there last year and had a good time. I think ppl there are generally ok and friendly despite having lived through terrible times during the Pol Pot era. Almost everyone has a relative or friend who was killed or maimed during those times. At these places I negotiate upfront but not too hard. Then at the end of each day, give the driver a small fee - say $1 or $2. Average tuk-tuk rental per day is USD 10 for the main temples. For the wider perimeter temples, USD 15. If you go for the further distanced ones (30km away and further), it will cost several times more, and you have to get a taxi or minibus.
U need only two days to cover the main temples + outer perimeter. So USD 25 max. I think now is now off-season (I went in Nov which is near peak i think), rooms for singles can be gotten from USD 10 onwards - I think USD 15 is max. Most cases, the bed is a double anyway.
* Add : forgot to mention, in my case, the tuk-tuk driver also served as the guide. Of course, don't expect to get a commentary on the history of the temples. But the drivers knows the place/temple names, how to go and which sequence. Read the tour guide books for the ones not to miss - the usual being the Tomb Raider tree.