I never really thought about it before, but also, I've never found a groomer that I was happy with an repeatedly went to. I've found the average price in my area is $35, give or take. I took Alphy today and they also clipped Abby's nails (a challenge and they were great), it was $35 for the cut and $5 for then nails. I gave her $50 total because they are way nice and I know he got tons of personal attention. I would pick them over Petsmart any day.
I am way under tipping my hairdresser though based on what you guys said. But again, I think it's because I don't have a regular one that I use. Still looking.