Your question is wrong.
A fair price is whatever you and the customer agree on. It is your job to maximize your income. It is not your job to save money for your customer.
There are many ways of calculating markup. Start with wages. You can start with direct wage cost then add a percentage to cover all overhead or you can calculate actual wage cost. Actual costs include:
...Direct Wages
...Workmens Compensation
...Liability insurance
...Health insurance (if provided)
...Vacation costs (if provided)
...Employers FICA and FUTA
...State unemployment ins
...Federal unemployment ins
...Office burden
...Management burden
...Cost of tools provided
...Cost of vehicle (if provided)
...Cost of payroll service (if used)
...any other employee costs.
These will get you what your employee actually costs you hourly. To this you must apply a factor to cover indirect overhead costs (phone, licensing, office expenses, training, etc.) then you will have a cost to use for each employee that just might get you to break-even on an employee. As a practical matter, there will be days when the employee doesn't perform up to speed and days he screws up materials, costing you money. You better include a fudge factor to cover those costs. Depending on the competence of your employees, this could be substantial.
Of course you're not in business to just cover your costs. Consider your investment in time and effort as well as tools and equipment and factor in a fair return on that investment. Add this to your employee hourly cost also.
Now, you've covered your employee costs, add another factor to provide you with a profit.
Generally you must charge at least 3X your employees hourly rate. If you provide a truck/van, tools, training, etc. you will probably need to charge 5X your employees hourly rate, and possibly more.
There is no simple answer to your question. The fact that your asking it is a good indication that you are already on the road to failure.
