i built my own polytunnel this year out of conduit that was got through an electrician friend and all i bought was the cover.
the only problem is that i cannot keep it were it is now(long story) so i am going to have to take it all down again and move it else were. but hopefully not for a month or two as my vedg are not all ready yet.
i have been getting courgettes,radish,herbs,beetroot,chillis,peas. so not doing too bad.