Well I can tell ya that we have a fantastic groomer and she absolutely HATES it when someone tells her to shave a dog. Even when we bring in a new foster, she tries everything to get out any mats first and only shaves if absolutely necessary.
She charges $38 for the shampoo, dry, cut, bandana (ours refuse bows), nails, ears, and anal glands.
We go every 5-6 weeks and it does get pricey with 5 of them and a foster or two.
I am looking into to learning more myself and have ordered a table, clippers, 3 different blades, dog tub, two different scissors and a comb from PetEdge...it was pricey to get all the stuff, but pales in comparison to the groomers bill every 5 weeks.
Once my wife gives me permission, I will order the video!
We plan to still have them go to the groomer, but would like to move it out to every 3 months, but will definitely have to do some heavy maintenance in between.