BuyDig offers the Aeon Labs Z-Wave Smart Energy Meter for $19.99. Coupon code "EZWEM5" cuts it to $14.99. With free shipping, that's tied with our March mention as the lowest price we've seen. (It's the best deal now by $13.) This device measures and wirelessly reports electricity usage. (You'll need to buy a Z-Wave controller separately to view the statistics.)