A light table is actually pretty simple to build. It's just a platform to hold a light with a transparent surface. A web search will turn up several DIY options. Here's a very simple light box tutorial. If you build your own, make sure it's not a fire hazard, yet bright enough for tracing. There are many tutes for making light boxes for preschooler activities right now, so make sure the tute you use is suitable for tracing.
I have an old light box that was given to me. The plastic surface is getting a bit yellowed and dim, and it's bulky. I like it though and it works fine. Now there are digital and LED versions available, but they can be spendy. They are nice and slim though.
If you have a tablet computer device (iPad, android tablet), You can use a drawing app with a bright white "page" or even a flashlight app to provide light and after you first protect the surface with a piece of glass or Plexiglas, you can use it as your light table.
|Can you see the Plexiglass over my tablet?|
You can also use a clear acrylic extension table with a light under it for the same purpose.
You can pick up some good battery powered lights for this purpose or even a string of LED lights.
Then there's the super easy to store version: Using a window! Tape your design to the window with painter's tape and then tape the fabric over and trace away. Granted, it's a bit awkward if the neighbors can see you. But you can't beat the price.
You might also gather from this post that a sheet of Plexiglas is a handy tool for a quilter. I'll save that for another post. Yes, I'm getting to be a tease with my posts. But it keeps me posting more regularly and keeps the posts a little more concise.