RB, my apologies, from your post it sounded like you did not tip, and most people seemed to assume that you didn’t. The delivery man did ask the appropriate question which was how much change would you like. HE could have assumed that you were giving him the entire amount as a tip, which he didn’t.
As far as claiming FREE DELIVERY is concerned….it is still considered FREE delivery since the STORE does not charge the fee, it is totally up to you how much YOU decide to tip. $3.50 is not a big tip on a $50 order. It would be a very nice tip on a $20 order. If you regularly receive a delivery from this store and it is holiday time you might have given this regular delivery guy a $20 tip. So it is FREE as far as the store is concerned since they are not receiving the payment, it is totally up to the customer how much he chooses to tip.
Our grocery stores do not advertise FREE DELIVERY and does charge a $6 or $7 fee for delivery. This is specifically to pay the driver. I don’t feel it is necessary to tip the delivery man because I know that I had already done so at the register. When I did have FREE DELIVERY, I used to leave a tip with the cashier knowing that I would not be at home when the delivery was made. When I took groceries home with me and had someone help me to the car, I tipped him as well and if it was raining or snowing I tipped him very handsomely.