The greenhouse is built entirely from salvaged materials - either donated or collected from rubbish skips.  All the concrete blocks and bricks for the foundations, the windows, screws and other fixings, even the tools were scavenged.  The only thing I paid money for was the internal water butt (and that only because I didn't realise until I started looking just how much valuable stuff people throw away).   It took a month to amass sufficient materials, and the process illustrated the power of positive thinking. Whenever I went out looking for something particular (as opposed to picking whatever I could find that might come in handy one day) I always found it.
 
The main problem was finding space to store all the stuff I'd found, which spread all over the tiny back yard and along the side of the house.  The other problem is what to do with all the materials I didn't use -- I couldn't bear to throw it all away at the time, and now I haven't got a van to take it all to the tip.
 
I was in the throes of M.E. when I built the greenhouse, and it took a month to get the basic structure done.  If I were fit it would have been a weekend's work  At one time I had the strength only to climb the ladder and hammer in one nail before going indoors to rest, so the pace of construction was not rapid. In fact it still isn't finished, because as soon as it looked like a greenhouse Josie filled it with plants and I couldn't do any more work on it.  She's been using it continuously from about 2 months after I started building so at least I can see that my efforts were worthwhile.