I have a coworker that I found out lived a mile away from me. Currently I live 18 miles away from work and it is cold out and he has offered to pick me up and drop me off. I am directly on his way and he said he doesn't mind because he likes the company, and doesn't want me to drive (prefers his car) and refuses gas money.
I like this arrangement, based on gas alone that saves me $5 per day. I have offered to buy him lunch but he normally brings his own in. Should I try to compensate him? I was thinking of getting him a gift certificate to a place he likes.