Kill-a-watt meters are available from most libraries (free obviously) as part of energy conservation plans. It's great if you just want to use it to tune your rig after building it, troubleshooting or getting a baseline average for your KW/h to estimate your power bill.
For some it might be better to just buy it (under $20 on Amazon). For other's like myself its a great to borrow it for a week or two to tune and test new rigs. Plus I live a few blocks from the library
That's a good tip. I was thinking I might buy one but free is better. There's not much margin in mining these days.