Greenhouses, Old Doors, Windows
Greenhouses are a lot like spring flowers. You can pay big bucks at a nursery or boxstore to get the showiest possible flowering plants, specimens which have been mass-produced in a greenhouse factory elsewhere. Showy springtime flowers have excellent WOW appeal at the time, but begin to fade right away. Home greenhouses with polycarbonate sides are similar: they look good out of the starting blocks, but the sun and wind give them short lives.
Old doors and windows will last. The cost can be almost nothing. As with Lego blocks, they can be pieced together to achieve creative and pleasing architectures, though some gardeners might not care for beauty as such, preferring strictly a utilitarian approach (at the worst, it can be a rural slum). Old sheds can be pressed back into service by replacing the wooden or metal siding with glass.
Recycling old doors, windows, and sheds doesn't mean that the gardener is poverty-stricken, however. Even some millionaires like the challenge of not wasting money on simply buying everything new and having it installed by so-called professionals. Who knows when Depression era skills will be needed again?
10x16 greenhouse in SW Ontario- salvaged windows for the glass, salvaged doors, an old deck for 1/2 the floor and the other half is discounted paving stone. The walls that aren't glass are insulated and the north side of the roof is insulated and asphalt shingles. Several back and side windows open and there is an automatic venting window in the roof near the ridgeline.