Although most places charge by the unit, I think this can leave people confused and unhappy. I our practice, we charge by the area treated. Each area in the upper face costs $175. Typically treated areas include between the eyebrows (glabella), the forehead, and in the "crow's feet". First-time patient discounts and other specials often apply. There are several benefits to charging by the area:
We use as much Botox as is necessary to work, but don't overuse
You are guaranteed the muscles will be paralyzed. If not enough was used, touch ups are done at no cost. Again, you pay for the area and not the amount of medication used. Its my job to make sure I use enough.
You know exactly how much it will be before you come in. No surprises.
As a side note, I typically use between 20 (one area) and 60 (3 areas) units for the upper face, so the total cost is less than $10/unit.