That's probably the most asked question. This was about $40K for everything. The polycarbonate is guaranteed for 10 years so the project is amortized over that period. $4K a year in veggies out of this building won't be a problem and we can grow year-round.
I built a modified version of this geodesic bio dome a couple of months ago when I wanted a economical greenhouse. The plans say it can be built for $200... it was a bit more than that, but I also made mine bigger and did some modifications. Still pretty easy to do and within my budget.
That looks cool. I chose a 3v format for my geodesic dome, even configurations required just too many struts and connectors for a similar volume size. But I'm glad I went through the trouble because I do not like greenhouses caving in under heavy snow falls, while this geodesic structure is super strong and stands up to anything.