We run around $700 per month in the warm weather. And yes, I know it's a dry heat - so is my oven but I don't like to spend much time sitting around in there.
That's much lower since we insulated the ceiling.
7200 square feet, including showroom and non-cooled/uninsulated warehouse, also upstairs office space. We only have two spas running at present, but have had as many as five.
We use gas to heat, so in the winter it drops to well below half of that.
8-)