There are many factors in determing your starting prices as a freelance barber. The four main factors being time, talent, economics and expenses.
Time: When providing your services, are you being thorough or are you just flying through the process ? People know when you are rushing them, so keep that in mind. Customers appreciate a detailed and articulate barber, who know what he or she is doing. That being said, don't keep them in your chair for all eternity, thats even a worse scenerio.
Talent: Know your worth, and be honest about it. Don't sell chopsteak at Ribeye prices, or you will be out of business quicker than a blink of an eye. If you can't determine this on your own ask your fellow barbers if your skills match the your pricing. I say this because I know barbers who shouldn't even be cutting hair, let alone charging premium prices. If you already have a dedicated following, this is a good indication of your worth.
Economics: Barbershops are everywhere these days, get out and take a look around, make some phone calls and see what the current rates are in your area. You should be able to come up with an average price that matches for your skill level.
Expenses: This can easily be detemined, just average out what it will cost you to maintain your business. Rent, products, advertising, taxes, etc. Write this all down on paper or spreadsheet. See where all your money is going and determine what you'll need to make reasonably comfortable living.
When all is said and done, set your prices, see how things pan out and go from their. If you're reasonable and honest it will all work out. Your next step to increase your bottom line should be to add more services, sell products, and do other income producing activiities outside of barbersphere. I personally recommend the the internet. Why ? Because "the internet never $leeps" !