The pricing structure definitely varies a lot between providers, and it can be confusing! Unit-based pricing tends to be more transparent because you're paying for exactly what you're getting. Each unit treats a specific amount of muscle, so the number of units you need depends on the strength of your muscles and the severity of your lines. Area-based pricing can sometimes be less predictable because different people need different amounts of product even for the same area. When you're comparing prices, make sure you're comparing the same thing - some places advertise low per-unit prices but then require minimum purchases that drive up the total cost.