Christmas Lights - Power Consumption

I've been running my mulit-colored Christmas lights (as shown here) for a few weeks. Living above the 45th parallel being in the winters, it gets dark early. I've set the lights to turn on at 4pm and run all night, turning off at 7am. I've been using a Kill-a-Watt to measure the total power consumption and here's where we are, a week before Christmas.

...And I just remembered we lost power yesterday so the Kill-a-Watt reset. So, uhmm, after 24 hours of operation the lights consumed 0.31 kWh.

Assuming I run this for most of December (we'll say 30 days), this means the total energy consumption is 9.3 kWh. At $0.06/kWh, the total operational cost of running the lights is $0.56. 

This my frugality can handle.