Here in the state of Oregon, the Oregon Energy Trust purchased a bunch of
Kill-A-Watt meters for libraries all across the state.
LINK: http://energytrust.org/library/build-energy-awareness/kill-a-wa
I did a quick Google search and noticed that there are many other states
with similar programs. Consider checking one out from your library instead
of investing in your own. My library allowed a two week checkout which was
plenty of time for me to check the electrical devices in my home.
YMMV! Good luck!