Varies by area, since this has to be based on what yields a fair living wage for you as well as on what the local market will bear.
My standard advice is to invest in a Flat Rate Manual -- I believe several are available from the usual locksmithing publishers -- which is essentially a spreadsheet in paper form to help you determine what your proper hourly rate and trip charge should be to cover running your business (salary, rental, inventory investment, vehicle wear, advertising...) and leave you a profit you can live on, and then multiply the hourly rate by reasonable estimates of how long various common jobs should take to obtain appropriate per-task fees. Then check that against your competition's posted prices to see if you're being unrealistic... while remembering that some folks do charge an unreasonably low price and should NOT be matched unless you too want to have your business fail.
Actually, the safest way to learn this skill may be to watch someone else do it for a while -- hire on as an employee for a few years rather than trying to immediately strike out on your own. That'll also teach you just how much of the business you do and don't know, which will help you decide whether you're really ready to attempt going solo.
Welcome to the joys of running a business. Many, if not most, new business ventures fail due to insufficient planning and unrealistic guesses; don't be one of them.