http://www.qcover.com
Cheapest and easiest hoop structure I could find to put up. I just finished a 36'x60' structure that will easily hold 180 rolls, more if I try a little harder. All materials ended up under 10 grand. Gov't cost-share put it under 5 grand. It took me two Saturdays to set all the posts and build the pony walls. Took one Saturday to put up the frame and cover. That's about $2.30 cents a square foot to store hay. If I fill it every year for ten years, my cost comes to about $2.66 per roll of hay. Pretty reasonable I think.