Dental Cleaning/Extraction for Dogs

We adopted a senior corgi mix who had poor teeth. She had tartar around her upper back teeth, and she has toothaches. Our vet recommended extracting the back upper teeth, but we want to explore options for moderate periodontitis. Since we live around the Galleria area, most of the locations near us are costly for dental cleaning and/or extraction. We have noticed some express locations that perform routine caring, but she definitely needs advanced treatment.

1. What is the reasonable amount that I should expect for these procedures?

2. Have you had a positive dental care experience with a vet for older dogs?