Heh I built my own out of a CVS sanitizer light (same uv light) and a metal wood chip smoker box I found at Sears Hardware for $5. In the end it was about $20 altogether (including my buddy's CVS discount. Its literally just taped together right now but I'm going to redo it with some black duct tape.
I erased a few with it so far but I never realized the light didn't have to be lined up with the window. Once I find some time again I'll try a handful in there and see what happens.
I use the timer on my iphone to time them.