My experience with hair stylists is that they look at my hair....after they do it....and then tell me how much they are going to charge me.
I've gone to a stylist one day and he/she will charge me $1.50 (as an exaggerated example). Then, I'll go back a month later to the same stylist and get the exact same service and then after they do my hair they charge me $2.50.
This has happened on several occasions with different stylists in different salons.
In my case, I do not agree with tipping that stylist with an exorbitant amount of cash when they have floating pricing system on my hair.