This is what I used from April til about July..
http://www.lowes.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10151&catalogId=10051&cId=SEARCH&productId=3191829&cm_mmc=SCE_gps-_-gps-_-gps-_-SPRING%20GARDENER%207H%20x%206W%20x%208L%20Gable%20Greenhouse%20IS%2070608
Once the weather was suitable I took them out. We have wayyyy to much rain in our area which is why I bought a few.. They were 199.99ea when I bought a couple of em.( I have 3 now) it has 4 roll up windows, 2 zip up doors, so basically you can ventilate it in many ways. I staked it to the ground on all six legs incase of a storm. I think it's a great value and it worked great for me. I will tell you once the temps started rising it was a daily chore to make sure the temps didnt exceed 90 degrees. I saw them hit a 100+ too many times.. My plants look great though. And by the looks of the weather here I'll be putting them back in ina couple weeks for a month before bringing them inside. I wouldn't recommend a greenhouse all season.. They get wayyy too hot and it's impossible to keep em cool after 80 degrees or anything near.. but for the first bit of spring and the last bit of fall.. It sure helps, and extends your season.
hope this helps
Good Luck!
Brandon