I converted an old shed into my coop so most of the work was already done. I took a lot of material from my old run and recycled it for portions of the new run and used the 1/2" HC to cover window openings, etc. I still ended up spending about $2500 and this was in the spring/summer of 2019.
Some might say I went overboard with predator proofing but nothing has ever gotten at my flock within their pen and I sleep like a baby at night.
The way I look at it is the chickens are my main source of entertainment and stress relief. I don't go out much so I'm not spending money on that, why not on the birds? I've NEVER regretted it.