Our mens shed used two old 40 foot truck containers 7 put some 50x 50 hollow box covered in wriggly tin with truckload netting across the back .
At another place I've visited recently they had two furniture pantechnicons ( sp?) 20 foot apart and had welded upl an 18 inch high A frame set ( 6 x off ) for the roof . They used self tapping high tensile TEC screws to fit three rows of purlins made of wooden planks & used shorter TEC screws to fit wriggly plastisol tin on as a roof .
The back had a split curtain of green truck load netting , so did the front but the front also had some blue water pipe cable tied to the bottoms and were fitted with two pulleys & ropes on each curtain . So the front curtains could not only be slipped to one side a it to get in th shelter but they could be hoisted up out the way if & when needed.
One of the best cheap shelters I've seen was made of the massive square bales of straw , arranged as a letter U with an external door way at the back cut in using a chainsaw .
The roof was simple home made sterling board trusses , made glued & nailed at 20 inches high by about six metres in length , then glued & nailed on old roof timbers
They nailed a few reclaimed floor boards across the trusses, top , bottom & middle , blinded the apex with several layers of old carpet ,then covered the roof in a nylon hay stack net weighted down over several old curtain sider lorry side panels , that they'd used as tarps.
Using old car tyres touching each other along the sides filled with a bit of soil in them for the weights .
It was five years old when we left the area and had stood up to some horrific storms without any problem .. the back door opening was the secret to not having the storm force winds lift the roof off
Another one made like that at the same place was a lot smaller and had a flat roof covered in curtain sider sides which were weighted down all over the roof with single layer of small bales of straw ,