Hi
@binfordw and welcome to the forum
I hear flat, open and Indiana in the same sentence, and I picture a lot of wind, and a lot of snow in the Winter. A greenhouse that will withstand these conditions would be my primary concern, but you won't get a good quality one of the size you are looking for below $6000...unless you build it yourself (and even that I think is a "maybe").
Take a look at Solexx (
http://www.solexx.com/index.ht...) and Growing Spaces (
https://growingspaces.com/best...). I don't have experience with either, but both are supposed to be excellent for wind and snow loads. (
@plantmanager (Karen) owns a Growing Spaces Dome, and she lives in a windy area. I know she'll be along on this thread and will comment.)
Conleys (
https://www.conleys.com/) will engineer a greenhouse for your specific wind/snow loads. They are not cheap, but a few years back, I thought they were reasonable for structures they offered.
I looked at Climapod a while back, and I came away with the same impression you did.
Keep us posted with what you decide to do.
Jim
