Work out the floor first, because it is arithmetic rather than opinion. Take what you need to earn in a week, divide by the hours you can realistically sell in that week — not the hours you are open, the hours somebody is actually in the chair — and you have an hourly rate you cannot price below. Add rent, insurance, software, card fees and product to it.
Then cost the service itself: your product for one client, the consumables, and the true chair time including setup, cleaning and turnaround. A ninety-minute service that occupies you for two hours is a two-hour service for pricing purposes.
Only then look at what others charge, and treat it as a sanity check rather than as the answer. Pricing to match somebody whose costs and speed you do not know is how professionals end up busy and broke. If your number lands well above the local range, you need either a reason a client can see or a faster way of doing it.
Price the first few as an introductory rate with an end date if you are unsure, and use them to time yourself properly. Raising an introductory price on schedule is a normal conversation; discovering six months in that a service loses money is not.
Add a starting-price band where the work genuinely varies, and say what moves it — length, thickness, removal of somebody else's work. A 'from' price with an honest explanation beats a fixed price you have to renegotiate in the chair.