Does Avis actually charge for car seats? If you google the Avis coupon sites, I would guess that you will find a coupon for something so esoteric as a child car seat. For that matter, rez agents tend to be pretty helpful, if you ASK them specifically what kind of coupon you are looking for, they will tell you if there are any coupons valid during the time you want to rent for. They are willing to do this because the car rental business is so competitive, and they know there are coupons for other companies out there. However, you must call, and you must ask.