I stayed one night at the Arunas Hotel in Kampong Thom, last April. I think I paid $20 for a double room.
It is located on the main road that leads from Phnom Penh to Siem Reap. A bit noisy but you can request a room away from the main road. The entrance and lobby is tiny. They have a Visa sign at the front desk but told me that they do not accept it. Elevator is also very small and slow but I heard that it was the only one within a 100 mile radius.
The room was spacious and clean with reliable hot water And wifi during my stay. The balcony had a good view of the local microwave tower and consequently had the best cell phone signal strength during my entire stay in Cambodia. The attached restaurant is large and serves a wide range of local and Western dishes. I thought the price was a little high by local standards but very delicious.
I would certainly stay there again.