Woah! $57 plus shipping? That's a lot of money for $20 or so in parts. The motion sensor is from a $14 security light. That plus a junction box (which doesn't have to be metal like that one) and some cord is all you need. In fact, you don't even have to go that far. You can use the security light as-is and put in two plug to bulb adapters. There's a good how-to in the tutorial section that goes through the whole process.