Grooming does not, by law, require licensing or any kind of formal training.....Meaning any one can say they are a dog groomer and cut your dogs hair.
With that being said, I attended Academy of Animals Arts in Largo Florida and passed their exams with flying colors to become a professional Pet Stylist. I am also an active member of NDGAA & IGA where I am working on my Master Groomers Certificates. I also compete. I attend yearly grooming seminars as well as host seminars for local groomers. I am certified in Pet CPR and have many Academic Certificates related to grooming to make sure I am up to date on safety protocols, shampoos, ingredients and products, as well as techniques.
Please, whoever you decide to let care for and groom your pup, ask questions. Ask what continuing education they do, are they certifying, do they compete, are they members of any associations, are they trained in k9 CPR. These are all important questions. And in turn why some groomers charge more then others. Education is not cheap and should not be put on the back burner.