Hoop coop would be a super simple build. I covered the entire structure with 1/2" hdw cloth, including a skirt. Then the top can be weatherproofed with a heavy duty tarp.
An other super easy build would be a shed style coop, and you could modify the shed style to make it a wood's open air coop.
You've learned from experience that a pre fab is a poor use of your $$$!!! Any thing you build will cost less and yield much more usable space for a fraction of the money.
I'm a 61 year old biddy, and would much rather be working in the shop with power tools than pushing a vaccuume cleaner (see, I can't even spell it, let alone use it well!) In the last 5 years, I've built a hoop coop, 2 tractors, a green house, helped hubby build a big coop. And, I also spend time using my chain saw. If I can learn how to use power tools at my age, you can do so. A positive note: I still have all of my fingers!
Yes, HDW cloth is expensive, but it's no where near as expensive as the poorly designed, cheaply made, over priced pre fab coops. Why don't you sit down and price out the materials for a 8 x 8 hoop coop. I'll get you started. You're gonna need: (2) 16' cattle panels, (2) 2 x 4 x 10' and (2) 2 x 4 x 8' studs for bottom framing, (1) 2 x 4 x 10' for center ridge pole, extra 2 x 4's for end wall framing. Your choice about how you make the door, and whether you close in one or both end walls with plywood or corrugated panels, or leave them open with just the HDW cloth covering. Then you will need to figure out how much hdw cloth to buy. It comes in 2, 3, and 4' wide rolls. Cheapest sources are on line. Miscellaneous screws, and other hardware.
If you go with a shed style building, check out "Sunset sheds and garages". Plenty of designs there that you can adapt.
You can buy windows and doors at Habitat for Humanity Restore for a very good price. I can pick up free windows and doors at my town dump on a regular basis. Get those before designing your building.