Hello,
Insteon products hardly ever go on sale and I recently waited until SmartHome.com had their 20% off coupon during the holidays to jump in headfirst with finally updating the automation for a new home. There were a few devices that I forgot to put on that shopping list and have been looking elsewhere for the best deals. Surprisingly, I found the lowest pricing ever at Costco.com. Dimmer switches for $37.50 each (pack of four), door/window sensors for $25 each (pack of four), and motion sensors for $30 each (pack of two). They offer a few other Insteon products also, so go to Costco.com and just search for Insteon to find them all.
Good Luck,
Dr. Z.