I research at multiple repositories in Washington, D.C. and in Richmond, VA, and closer to home in Fredericksburg, VA. For research in Washington or Richmond I charge $55 per hour. The minimum charge is for one hour, unless I have work scheduled for multiple clients that will add up to at least one hour.
To help in estimating how much time your work will require, military pension files average 1 hour, homestead records average about 45 min, and compiled service records, military bounty land warrant, and cash entry land records average 1/2 hour or less.
For Fredericksburg or online research, I charge $20 per hour. Since my travel time and costs are minimal, I do not require a minimum amount of paid work for local or online research.