There's also plenty of places to buy food in Philly. You can walk there across the bridge, but it's something like a 30 minute walk each way (so not ideal for a proper grocery trip). There's also buses to/from Philly, unless that's changed since mid-2011.
I assume the notorious Dunkin' Donuts store is still operating in Camden.
Philly is not exactly packed with grocery stores either. Without a car getting across the bridge is the easy part, you then need to get to one of the grocery stores and get back from it with your food. That will take a while, even on buses (which are rather poor in Philly), so in order to make it worth your time you will need to get a lot of food at once... which is difficult without a car, even on buses.
I assume the notorious Dunkin' Donuts store is still operating in Camden.