The $2.99 is probably seasonal. Gas will be above $2.99 next summer most likely. My memory is a little fuzzy on the way this incentive worked. If it is based on a special card, then don't use it right now and save it for the summer. If it is based on a credit card, then use a different credit card, or use cash would be my advice. No sense in paying more for no reason if you ask me. I would use the incentive during the summer for two vehicles (offer a family member or friend to share the incentive for some money) and not use it during the winter.