This Light Box is made with foam boards and it can be done within an hour. Here is how....
1. You will need two of those. You can find them in any Wal-Mart store in the section where Bristol Papers are. They are 22" by 28". You have to cut them in half to have 4 boards of 14" by 22". Use 3 of these boards for sides and back panels. Cut last fourth panel into 2 pieces - one is 14" by 14" will serve as top (roof) panel and second is just 14" by 8" which is enough for bottom part to hold the shape.
2. All walls are joined with masking tape. As you see in the Ready for shooting picture I have fixed lamp with daylight bulb that I can't use in position other that lightening from the top. To accommodate this setting I made an opening covered with trace paper (from any dollar store, craft section)
3. Place lights on both sides of your light box and as it shown in my case I place top light through the window. Make sure your lights on sides beam to the opposite wall to have defused effect. Now it's ready for shooting.