make em - cold frames are soooo easy. Any old timber for the sides and an old window for the top.no need for fancy hinges or anything. I would rather use plastic but mainly because my glass has been mashed by a million footballs. the stuff I get from my builders merchants is clear polycarbonate and costs about £15 for a decent sized sheet (can't remeber exact size, about 1m x 1.8m. I like to line mine with sheets of polystyrene - loft insulation, dead cheap. I think you can easily use breeze blocks or bricks to construct sides too. Good luck
