Other than the seats, it looks like about any other blazer from that year with possibly a little less rust. Maybe he gets a little credit for the seats and bumpers but it still only has lap belts. Seems like it's at least $2000 high.
If I'm seeing the pics right, the axles haven't been swapped, it has original wheels (could be new or painted), the door panels and arm pads need to be replaced, no carpet or lining, average home built stereo, no side panels, no engine pic? This makes me wary, why not show it off if it is a crate motor. Maybe it's 10 years old. Is the A/C compressor missing?
Also note the tailgate motor might not work or need a cable, trim parts. Yeah the fenders were replaced but it probably needs a new hood as it looks like the passenger side is kinked/arched. That rear quarter panel will take some work along with filling the holes.
I'm not sure what's up with the "megashifter" other than it looks like it's not mounted to the floor. Is that a doubler in there (yellow twin sticks)? If it has a doubler then it's only $1500 high. I'm betting it rides like a rock and needs new shocks too.
If it were painted the door interiors were replaced, I might pay him $5000 but definitely not in that condition although I'm not familiar with the CA market on these things.
If this came off harsh, sorry, I'm tired and grumpy but if I were your I'd buy it as a project and plan to put at least $2-3,000 in to it if you want a nice ride or get something newer for that kind of money.