I switched to Direct Energy on 2/1/2012 with a month-to-month flexible base rate of 7.4 cents. I was expecting the rate to go up during summer and down again in the fall.
The 1st increase happened in April, rate became 8.2 cents. It increased every month up to 11.2 cents in July (base rate). After that, it went down to 9.8 cents were it stayed until now (December).
In the meantime, they are advertising the rate online as 8.2 cents (printed website page on 10/26/2012, as well as today 12/15/2012). When I complained, they told me I can switch at any time.