Electricity rates in Texas are not fixed. Your rate can vary greatly depending on your usage and your electric plan. Some plans have relatively flat rates, while others can be all over the place. This means that you could end up paying 7¢ for 999 kWhs and 8.5¢ for 1001 kWhs. That would be a 16% increase because you microwaved a few potatoes. Learn more on the different plan types here.

The most important thing to do before you sign up is to READ THE EFL! This is the only way to truly know what you will be paying and will ultimately let you know if the plan is a good fit.