I guess it's like anything else. Depends on service. Although they kinda have you over a barrel. You are depending on them picking you up for the airport on time. Our first time using a "limo" I think we tipped $20 each way. But the driver was great, talked to us the whole way to and from the airport. Pointing out interesting things and stuff. He took all our bags from airport to car to OKW and vice a versa. Great person, alot of fun. Now if it hadn't been so well, maybe $10 each way? Wouldn't want to be to cheap and make him upset. Also could depend on if you are making a grocery stop or not.