Of course they charge for carseats, as a matter of fact they charge a hugh amount for carseats $9/day max. $50 per rental per seat. I know that because we needed 3 car seats for a 10 days rental at DFW. So we decided to fly our car seats over the Atlantic to save $150. I think Avis is trying to earn money on these items in order to bring down the net price so that they can match other car rental companies.