Assuming a delivery worker works 5 hours a day for 5 days a week, that's roughly 35,916 usd. As a PhD student that hits hard.
But I also lived in a LCOL city where my rent was $500 (room in an house with 5 roommates) and I lived super well.
And don't forget DoorDash doesn't pay for gas or other required maintenance from the extra use on your car.