As a former groomer, I'll softly suggest that you DO tip your groomer. I've worked in a lot of salons, and suffice it to say, a good tipper generally gets preferential treatment and their pets are treated better. (not at all salons, but if you're a repeat customer and don't tip, I shudder to think what may be happening to your pet! Sad but true a lot of times. )

9 times out of 10 the person grooming your dog isn't the owner and doesn't set the prices. They only get paid a percentage or a flat rate per dog.