You can find a new doctor, but it's really important to hold onto a good mechanic. It's probably the regular service industry that's hardest to find good, consistent providers in.
Even with CA's taxes/fees, 4 tires and an alignment should top out at $1300 for some incredibly good tires.
Edit: went and checked. Unless she has some super expensive SUV EV, you're looking at ~1100 USD before tax for the absolute top of the line EV tires delivered in CA. There's some fees, so it's probably 1200 for the set. They got a cool $600 for nothing from her, and I'm dead certain she didn't get as good of tires as I could find in 2 minutes.