If the guy is going to start from scratch, dig down a ways, lay in heavy rock, go over it with a vibrating roller, lay in another layer of smaller rock, roll that, then lay in a third layer and roll that, and finally topcoat it with a show coat that he doesn't roll, the price quotes sound reasonable. If all you're talking is tailspreading a few loads of crushed local stone, they aren't.
A lot depends on what the job entails and what kind of stone you're going to use, but I had about three times that much drive done from scratch, layering 6-10" sandstone, then medium stone, then crusher run, all packed down with a vibrating roller, for less than those quotes. A couple years later, I had a top coat of blue dolomite put down for appearances and the cost was pretty high compared to the previous work due to the fact that the stone had to come from 60 miles away rather than being local. Whenever I plow the snow, the only thing I tear up is the top coating of pretty stuff. The crusher run that was packed down is doing fine. Makes me wish I hadn't gotten the other stuff put on top.