Market value. Is that "Retail Value"? On kbb.com they have 3 categories, trade-in value, private party value, and retail value.

 

Basically market value is what your vehicle is selling for in your area. Which would be a combination I guess, of both the private party and retail.

You can use Edmunds
Used vehicles, used car prices, used car values at Edmunds

And do it as if you were trying to BUY your car before the accident. You'll get results that knock off or add on dollars for your zip code, for the miles, for the color, for the condition, etc. Which is what insurance companies do too.

It will be really low. However, then click on the button for "find cars in your area" and check out what they are really selling for.

For instance, if I pretend my car is a 2008, they tell me that private seller is about $13,265and dealer is $14,026.

Then I go to the whopping 4 cars actually available in this area, with only TWO being base models at dealerships (the other two are Sport models), and here are their prices:
$14,994
$15,893

With of course, way more miles than are on my car (I used my stats, as I don't know enough about your car and location to enter the info).

You may have to do a bit of wheeling and dealing to get a real market value from the insurance company.