My summer game this year is how to save on the AC bill. So far, my experiment (or game) is working pretty well as I've only run the units a few times.
To be fair, as your results may differ and your system different, my house is well insulated. I also have a wrap around porch on the south side of the house. I have two AC units, one for the downstairs and one for upstairs. I also have two attic fans. So I have some advantages.
Here's what I've been doing. First, I watch the weather forecasts like a Hawk. If the temperature during the day is going above 80 degrees, I shut all of the windows. I leave a fan on my by my dogs' kennels to keep them cool. If the evening is cool, I'll open the windows all around the house. Sometimes, I'll wait until late evening when the temperature has dropped enough (at least low 70s is preferred unless you've got some great breezes). The house cools down to start the cycle again.
If it's going to be fairly hot, then I'll set the AC upstairs on for the day at about 80 - 82 degrees. That keeps it from getting really hot and doesn't run too hard. At night, I'll lower it because it's not fighting the heat outside. Maybe I can turn it off completely. Only if it's above 90 degrees will I run the downstairs unit, then in the same way.
For example, I did this today. While it got up to about 86 degrees, the downstairs was only 78 degrees and upstairs was 81 degrees. And I had never even turned on the AC. It had been cloudy for some of the day which helped, but the house is ok, and with a fan, perfectly comfortable.
I've found that fans - ceiling and others - help and cost less than running an entire compressor and house unit. After I get a full month's bill - maybe two - I can see what I'm saving. But I know I'm saving a fair amount since the units are running so little.