Casa D'Acuna is THE best budget place to stay in Coban. It is located down a steep hill from the main plaza in Coban, on a quiet street. While rooms may be a bit more pricey than other hostels, the rooms are always clean, the showers have hot water, and a great restaurant is just a few steps away.
The hostel runs a shuttle service to Lanquin/Semuc Champey, Flores, and Guatemala City/Antigua, and shuttle driver Felix will give you great information about the area during the drive. They also have a daily tour to Semuc Champey with experienced guides. Also on-site is a gift shop with many beautiful gifts made in the area, and from local Mayan families.