Around $70-$110 raw on eBay (sold listings). There isn't much of a spread in grades until you get to high MS (MS 67 has a sale at $481 and another at $600 while MS 66 is $250-$300). The cheapest slabbed examples (MS 64 and below grades) can be found for slightly more than raw ($100-$150).
The pictures are too over exposed to tell. Over exposure covers up marks. I learned that the hard way years ago. The San Diego comes in high grades like MS-65 and 66. The lower grade ones are not easy sells unless they are very cheap.
From the pictures, it appears to be mint state and clean, blast white perhaps. I'd throw a hundred dollar bill at it. Here's the piece I have in my collection, MS65 -
That's usually my go to, but this person wants to sell to a dealer and I am just wondering what an honest dealer would offer.
I could see $50-$60. If it is nicer than my interpretation of the photo, then more (maybe closer to the $80 that @BuffaloHunter mentioned).