Last year I built a green house for the tomatoes on my raised bed in my garden (original post: http://tinkr.de/blog/garden-tinker-project-greenhouse-for-a-raised-bed/.
It basically consists of a wooden frame and air bubble film. As it turns out, after one year in service, the air bubble film is not UV resistant and it starts to get chapped and falls into little pieces. So it was about time to put a more reliable film on the wooden frame.
At first I removed the old air bubble film. Then I added a new roof construction, so the water would not stay on the roof, that has been totaly flat before.
Then I cut out the new film material, a fabric reinforced film for greenhouses with added UV resistance. The film was then stapled over the frame. I left the front side open and added a kind of a lid, that can be closed by Velcro.
After a couple of hours the green house was like new.
Costs: around 10€ for the fabric reinforced greenhouse film (available at ebay)
Tools you might need: saw for the wooden frame, stapler, folding rule, workbench, clamps, sharp scissors, marker pencil