Spent £25 on lamps and £24 on 20w output 100watt light bulbs
Cut 3 big squares out of a cardboard box (both sides and the top. Then taped the holes over with white parchment paper. I then added a strip of wallpaper on the inside.
Faced a light towards each piece of parchment and hey presto one light box.
Here's some pic taken in my light box.