I am a delivery driver for Papa John's, and our store charges $1.85 for delivery. We don't see any of it. That $1.85 goes to Papa John's to pay for insurance on us, and other such expenses that come along with offering delivery service.
We are delivering on our own gas, in the hopes that the customers tip us enough to cover said gas, with a little extra.
What the other person said is also true, when drivers have been doing it for long enough they get to know addresses. They get to know who is nice enough to help them out with $2-3+, and who just thinks "Screw tipping, it's their job!!". The latter usually are our last priority when we take multiple orders out. We don't do it to be spiteful, we just basically see it as helping out those who help US out first, then getting to the ones who don't care enough to at least help us put gas back in our cars.
I'm a Papa John's delivery driver.