a banner add caught my eye and led me to the above a 12v dc fan with a built in 100w heating element intended for heating an incubator for less than a tenner!!
ok a 100w 12v dc power supply is a bit bigger than the usual £shop phone charger plug used for a fridge fan, but iirc thats less than 5A or 5000ma so most established households with a modicum of cluter should have something suitable somewhere

anyway thought it worth sharing at least.. kills 2 birds with a reasonably priced stone perhaps?