Tipping your hairdresser

I get my hair cut at this expensive salon and the first time I went I paid 100 dollars and I gave her a 10 dollar tip because I thought you're supposed to tip them. Later my friend told me that you don't have to tip them! All that money goes to them...

anyway... Is this true? Do I have to tip her next time?

I think the rule is, you don't tip the owner of the salon, if he or she does your hair, but you do tip the stylists.

I tip my hairdresser according to how well she did my hair. If you don't want to pay for an expensive haircut, go to a cheaper salon.

yeah.
I think you should because that hundred dollars has to cover the hair die and there booth rental and also the food and house payment you know?

but yeah tip them

Yes, you can tip your hairstylist. It is always appreciated and they work very hard.
I used to be a hairstylist and I know that I certainly appreciated my customers leaving a tip, especially the regulars (people that came to me on a regular basis). If you are just going to a stylist for just one time, to get a cut or something, you don't need to tip (I don't think anyway).
Stylist work differently in different shops. Some pay a certain amount to rent a booth and they work for themselves. Others may work for the owner and have to give the owner a certain percentage of what they make, so they don't always get to keep the money they get.
I say, tip your stylist if she is good and you are their regular customer.