Greenhouses, Sheds and Sun Rooms - Budget Greenhouse: Is it possible?

I am reasonably good with hand and power tools and would be doing most of the labor myself, with some assistance from friends as needed.

Simply put, is it possible to build a small walk-in greenhouse (maybe 6' square, roughly), either via a prefabricated kit or by building it from scratch, that has hard plastic walls/roof (not plastic "trash bag" walls/roof) and costs less than $500, ideally less than $400? If so, how?

Boy..I can't imagine that with poly or plexi panels for that kind of cost. I remember Norm building a garden shed with the panels and they were like $60 each for 2 x 8 or something like that.

Heres a company that a Nursery owner told me about...he said he got quite a bit of stuff through them, might be some price info you can use.... Agricultural Supplies, Fabric Structures, Equine Buildings, Grain Storage, Livestock Buildings from FarmTek (http://www.farmtek.com/farm/supplies/home)

Unless you can find something at a salvage or surplus place....

Whatever you find for "hard plastic" for the walls, and whatever you come up for a roof that will work as a greenhouse is NOT going to fall within a $400 to $500 budget. You'll either have to change your plan, or change your budget.

It *might* be possible, but there are a lot of "if's".

If you're willing to do a makeshift semi temporary foundation,
If you're willing to use something like white corrugated fiberglass panels from a building supply store instead of nice dual wall greenhouse panels,
If you can make a lean-to style greenhouse instead of freestanding, (and bolt it to your house)
If you live outside city limits and don't have to worry about codes,

Then you probably could do something in that budget.