Without going into a long services analysis equation, the short version is:
1. Based on your skill level and available equipment (If you have to rent, the price goes up)
2. Based on your State's average price listing for hourly rates for said job (i.e., videographer, video editor, etc.)
3. Based on your area of operation and what that market will bear (i.e. Smaller Markets generally mean lower costs that Larger ones)
So based on those aspects you realistically appraise your skill level, how much per hour it costs you to operate your equipment, cost of consumables, and factor in your overhead (i.e. rent of the space you're working out of even if it's your house, electricity and so on.) When you average all that out, then compare your number to the average per hour in your state and raise or lower the price so that you cover your expenses per gig and still make a small profit.
The biggest mistake people starting out make is to underprice themselves in order to be competitive. Obviously, if you're not like Grinner and have moved into some fancy new digs with gear that's paid for and years of both experience and reputation to go with it, you're not going to be able to charge premium prices. On the other hand, you don't want to charge so little that you're working for nothing. Starting out you will have to do a few 'freebies' to get your rep built, but they should be just that few.
More than likely, you'll find yourself with a number between +/- $30 over or below the listed average hours and you can make your adjustments from there.