I did have most of the materials laying around. The only thing I bought recently was the PVC. The plastic was 'left over' from the wife's greenhouse. All the wood, door, and windows were salvaged and left over from 30 years of do-it-yourself projects. It's nice to have a big barn to store stuff
The PVC is the grey PVC conduit 3/4" x 10' that has a coupling built into it. A plus of the PVC conduit over regular PVC is that it is UV stabilized. We used to use it for high tensile fence posts and I'm still using posts that are 20 years old. I used two sticks for each hoop so they are 20'. I think the base was 10' wide. You have to be careful not to go to wide or the arch will be too flat and the snow won't shed off the sides and will take it down. Or at least that's what I've read.
The ridge beam is a piece of 1 1/2" PVC. I duct taped it to each of the hoops. It ties it together and also helps it shed snow. Halfway down the side I also taped a 1x2 furring strip to the inside to add some strength.
I wrapped the bottom, outside the hoops, with 2x6. I clamped the plastic to the top of the 2x6 with 1x2 furring strips. I drilled out holes in the furring strips for the screws so the screws would pull the strip tight to the 2x6.
I got the idea from this site and ad-libbed from there:
http://doorgarden.com/2008/10/27/50-dollar-hoop-house-green-house/And I still haven't spent much time in it! Though New Years day a friend came over to let me try out his new suppressors which was great fun.