The expense of a new shed style coop is the reason most of us build ourselves! It's expensive because of material and time. The time is the real cost. Unless skilled builders should undervalue their work? The ones I like are $800-$2600. Husband and I built a 6x8 human height coop on a trailer frame so that it could move to our farm from where we built it at. Materials ran about $450. Trailer frame was free. Took 4 solid days for two people, since we're "unskilled" let's say $10 an hour each, so $320. Typically though, you take your material cost and double it for labor.
The little pre-made coops you can buy online for $150-$400 usually require alterations or improvements for security.
Each hen, of a layer variety, is going to make roughly $80 worth of eggs a year, at market value of $4 dozen. Spending her yearly take a single time to build her abode, not too bad. 5 hens, $400. Consider how many chickens you want to have, then multiply that by 4 and that's the square footage coop you need for inside space. Times chicken quantity by 10 and that's how much outside space they need.
But a handy individual can certainly slap something together on a budget, and it can be easy. At the big box stores they have a saw, with good measurements you can take lumber home that's pre cut. From there you only need screws, a drill bit, a drill, a staple gun, stables, hardware cloth (sturdier than chicken wire), and a roofing material. Corrugated roofing is easy to cut with tin snips and there is a specialty screw with a rubber washer to screw it on with.
You can also scavenge off craigslist for material, once you have a pile and a plan you can hire someone to build something. We've hired people off of craigslist, you just have to explain things well and be picky with who you select. When we needed our wheeled coop moved it had some distance to cover, and it had a cruising speed of 18 mph, so we hired someone with a trailer to move it. I paid them $180 and they did the job well, with minimal joking about this giant purple coop they had to drag down the interstate. Hahaha!
Unfortunately though, this is one of those things where you either need to spend to get what you want, or be resourceful and pull something together.