Yes flexwatt is heat tape, and yes it needs to be hooked to a thermostat... As far as electric cost and a blue tongue skink vs a ball python..... You get charged by kw on you electric bill... the more wattage the more expensive it will cost to run obviously..... Most people i know recomend uv lighting on top of the heat.. so you will need something like a 125 watt mercury vapor bulb (these are not cheap) but you will be using 125 watts...... a heat pad appropriate size for a ball python will be between 7-20 watts depending on size... that being said you could run 6 big bp heat pads for every 1 125 watt mercury vapor bulb......