Cost for new tires

Hello everyone,

I just don't know how to go about researching this, it feels like I'm going down a rabbit hole. I have money to pay for it, I just want to make sure I'm not getting taken advantage of.

My 2013 Prius c needs new tires. I bought the car in 2017, so this is the first time I've done this.
I live in the San Francisco Bay Area, I mention this because I imagine that location can affect overall price.

I drive mostly in the city. Lots of potholes and rough streets. Every couple of months I drive to visit my Dad, about 500 miles round trip.
The tires are 5 years old. The tread is fine, but there are a lot of cracks in the sidewalls.
They are P175/65 R15, Goodyear Assurance.

In the past, I went to an independent tire store, he gave me a couple of options and I choose one.
I spoke with him yesterday, he quoted $776.92 for 4 Sumitomo tires, (I did not get the model number) installed and balanced, tax and disposal.
I do not have a Costco membership, so that is not an option.

The short version of this is:
How much do new tires cost installed?
Is the price he quotes "reasonable?"

Thank you all for your help.