One of the guys at the allotments made me a green house out of old frames. double glazing firms usually have to skip the frames they replace, and will gladly give them to you if you can collect them. i was lucky, local council houses were being upgraded..loadsa windows. Another plot guy had some perspex sheeting from old bus shelters which gave me a roof for a few quid. Grew loadsa stuff this year, and it's nice to sit in. good luck.
