Why is the sky blue: Rayleigh scattering
Neighbors did theirs themselves many, many moons ago and did a fine job ~ Father and Daughter. We opted for installers.We provided the sand and block they came with the machine and manpower and transit. I always think they best way to find out about any work of that type, where you hire someone is word of mouth. Folks will always tell you when someone "screwed them over"
For us the factors in price were, would we provide the sand and block, and how deep they had to dig down to level. Ours was x amount of dollars for X amount of depth (inches down) for X amount of diameter. Make sure you find someone who digs completely down to level. Everything went great until they burnt my manuals on cleanup so snatch those suckers when they open the boxes. He came in for the money he said he would and had the area leveled super quick,did it right, threw that pool up quicker than we ever could have done it. I don't think they were here for 2 hours to be honest with you. Had we done it on our own it would have taken a week or more I am sure. We would have had to work around weather throughout the days (he had a nice day and a machine for instant results) and our very slow, zero experience pace.
I am in PA and my install was 4 or 5 years ago so I don't imagine my price will be anyways comparable to yours ~ sorry I am of no help with current pricing.