If you're looking to maintain temperature, the method I use works pretty well.
I place the whole fermenter in a water bath. It doesn't have to be deep....maybe 5-6 inches deep. Then I place a tshirt over the fermenter so that it's dipping down into the water. This wicks the water up around the fermenter, and effectively "sweats" the fermenter. I turn on a fan in the room so that the air circulates nicely around the fermenter.
My room temperature ranges from 70-73 F or so, and the fermenter has not gone above 66 F. This method is super cheap and very easy.
I also add 2-3 frozen deer park water bottles (small ones) every day or two.