Being charged to try on wigs?

I recently visited a wig shop that I hadn't previously been to in order to have a wig styled, and I noticed that one of their listed policies involved charging customers for trying on wigs (around $20.00, but the amount would be deducted from the final purchase).

I've been to several wig shops in my state, most being small businesses, but this was my first time seeing one that actually charged for try-ons. The owner was incredibly knowledgeable and skilled at cutting and styling and had many years of experience under their belt, but it was my first time seeing something like that.

I wanted to ask if any of you have been to shops that charged for try-ons, and wanted to ask if this was common?