(This is my 1st instructable, so please be gentle!)
This is a small greenhouse very easy to build from a plastic fruit bascket you can get for free from you local supermarket.
You also will need plastic film, duck-tape, a plier and a sharp knife.
I already improve it to version_1.1 to avoid water pool on the top (see pics).
Cut off the button of the plastic bascket. Use the plier. Notice that there will be some sharp plastic edges witch I literaly melt off with a heat-gun tool I have (optional).
Place the plastic film on a flat surface and position the backet. I found it easyer with use of small pieces of dual side tape (optional). Then bend the plastic film to close all sides. Use a good strip of duck tape to end at both ends.
Trim the extra plastic film and apply more duck tape as shown.
My version_1.1 improvement was to place a wood stick to make a kind of angled roof to avoid water pool (optional).
I'm covering my seedling starter trays during windy and rainy winter.