I certainly wish I had one. Unfortunately there isn't a place in town that sells one.
I'm in the Yukon where in the winters it's cold and it's dark. The windows are really cold when I'm using them to trace (at 2 in the afternoon at work during my coffee break as that's the warmest time of day here...plus we have sun then).
So up to you and what you need it for...how much light you get where you'll be tracing, etc.