From the GOA

[JTHunter]

I've heard of this sort of arrangement before, but "sweat equity" on top of a $300 annual fee seems excessive, but that's just me and I have access to free public outdoor ranges were I live.

Part of the reason for these excessive fees is that, after being built, the county in which this range is located (St. Clair, IL), has had a running legal battle with them. The county has, to the best of my knowledge, lost every battle, but you know what protracted legal battles are known for doing to businesses and organizations.
One of the county's contentions was that this range would be under the flightline of one of the runways (the major one??) for Scott AFB, the county's biggest single employer. The AF never raised an objection IIRC, it was all the county's doing, so go figure.