Always check on the full price of groomers and what services they include. Many will provide additional services such as emptying the anal glands, cleaning the ears and eyes and trimming the nails as part of the package, but others will charge individually for these features.
When it comes to dog grooming, do not just work with anyone. You should concentrate on finding someone that you know and trust. Would you go to just anyone to get your hair cut, find a grooming expert that can provide you with the best skills as well as the professionalism that you are interested in.