Private investigation agencies charge from $40 to $100 per hour for their time. The average across the country is about $50 to $55 per hour. Those who charge less than $40 per hour usually live in very non-affluent areas. Most of these at the low end of the hourly fees spectrum are going out of business but don't know it yet or are subsidized by retirement pay and working spouses. Those who charge more than $55 to $65 an hour usually either have a good specialty and/or are located in an affluent part of the country. It seems most of them who successfully charge $100 an hour or more have advanced degrees or a strong link to some specialty market from prior employment. Capital punishment defense and hazardous materials investigations are good examples of high fee private investigation work. A trainee starting out in an investigation agency might be paid little more than minimum wage but could learn enough in a short time to increase his or her value substantially. A professional agency with a good client base would probably pay salaried investigators at least $25,000 and as much as $75,000 or more a year. Many agencies pay field investigators based on the amount of billable hours they produce for the agency. An average percentage for such an arrangement is 40%. If the agency charges $60 per hour and pays the investigator 40%, that would be $24 per hour for billed time. If the investigator has no personal life and can log 10 hours a day, over $5000 a month could be earned. On the other hand, if the agency does not have many clients, there might be only enough work to bill 10 or 15 hours a week which would earn barely enough to get by on.