I been living in Siem Reap for Three Years. I would like to inform people about the Agency Scam.
They are not interested in finding a economical place for you, the reason is that the commission they receive from the Landlord is the first Months Rent! So, if the rent is 800 USD per month the Agency receive 800 USD as a commission. OK, that is nothing you pay, but my point is that you might have a better deal if you work out the rent directly with the Owner/ Landlord.