(Odograph - n. an instrument recording distance traveled, especially by a pedestrian.)
I have a Kill-A-Watt monitor that I like way too much. It was a lot of fun for forty dollars or whatever. That device is intended to sit on the electric cord and total up the usage over time. That is the best way to use it, measuring (for instance) a week's worth of TV.
Alternatively we can use the monitor to measure the kWh for one duty cycle, just plug it in and check at the end of duty. This works for things like a bread machine (mine uses 0.37 kWh) or dishwasher (mine uses 0.62 kWh) where the issue is per-use rather than per-hour.
This calculator works out the cost for one duty cycle, and extends that out to the yearly cost of operation.
please enter some values and press "(re)calculate"