In the wintertime, Im usually under $100, around $70-$80 a month. Rarely run heat, and can open the windows a lot. Summertime, I run the A/C. I hate being hot, so Ill pay what I need to. During a really really hot month, its gotten as high as $180, but generally is around $130-150. Im very careful about turning lights out, and first thing in the morning Ill turn off the a/c and open windows, if its cool enough and the humidity isnt a killer, until the afternoon, when I close up shop and turn on the a/c.