I wish I would have kept a solid accounting. The shingles I had laying around, aluminum flashing was in a dumpster @ a job site, window was $10 @ a thrift store. Welded wire, 4x4 treated and outside sheathing were most costly. I guess I have near $650 in it. I used screws everywhere and bought a lot of brackets and structural materials for the base. It is very heavy. It does move pretty easy once its in motion. I intend to install a receiver so I can pull it with the lawn tractor. I thought moving it would be nice for the changing seasons. I can pull it into the sun for winter and complete shade for summer.
It has six nest boxes which is twice what it needs. We are going to block off one end for storage items and perhaps a deep cell battery should I decide to electrify the run or install a motion light. It really is an ongoing project so I am not at all surprised you continue to tinker with yours.
I think the coop itself is everything but bear proof and we very rarely hear tell of a bear around here. The run is another matter. Because it is mobile it is susceptible to digging predators. The ramp door is locked with a latch on the inside. Free ranging leaves the door open to a daytime heist by a fox (which I hear at night often) or bird of prey (a GHO was in the yard just two mornings ago).