http://www.snopes.com/photos/arts/xmaslights.asp said:
But, then again, with people spend $1000s on Halloween décor, it sure seems possible that someone would have taken the next step with their Christmas lights!
Other than the lights, the controller driving the sequence of the show would cost about 4 or 5 dollars for someone that has a microntroller programmer, or maybe 10 dollars to use a FPGA... Dunno how much the lights would cost, but I imagine they were purchased in bulk for a few hundred. Doubt the whole thing cost 1000s. The electricity bill will probably be a few hundred bucks though.