I've just finished to realize my cheap light box for tracing and it works great!
The project is very simple and cheap, I bought almost all material from Ikea, but you can use an old shoebox or whatever you want.
My lightbox is quite small, suitable for A5 or A4 sheets but you can do your own bigger and bigger than mine!
For this project I spent 13 euros.
I hope you like it... so let's begin!
(forgive my english, I'm italian...)
Start pasting the aluminium foil inside the box, on all walls, using vinyl glue.
Then wait for drying.
The foil will amplify the light.
In the meanwhile remove the cardboard from the picture frame, so youll'have only the frame and the piece of glass.
(I pasted the glass to the frame so it is more solid)