I don't usually post weird deals and things, but I just got an e-mail flyer that included getting Kill-a-Watts for under $20.
I think this deal is only good through Feb 11, 2009, so grab 'em while you can.
Killawatt purchasing link
That comes with free ground shipping and an "instant savings".
Add coupon code: EL20P on checkout to get your total down to $17.99.
Poof! Start saving energy for under $20!
I think I paid $35 when I bought mine.
The only down-side is that it comes in bulk packaging, but you didn't want that wasteful retail packaging anyways did you?
Kill A Watt P4400 - P3 International Electricity Usage Monitor - Bulk Package with Free Shipping
Monitor Your Electricity Usage, Kill A Watt, only $17.99
FREE SHIPPING
Coupon code: EL20P
Item# EL-006-0428