MTS

I bought mine many years ago at Michael's.

I don't see the exact model there now - mine was a bit larger - but here are some others:
http://www.michaels.com/Projectors-L...efault,sc.html

And more - most under $100:
https://www.google.com/search?q=+light+box&ie=utf-8&oe=utf-8&aq=t&rls=org.mozilla:en-USofficial