First things first: Your old digital camera isn't going to make you rich.
However, you can make sure your old digital camera stays out of a landfill, while receiving a payment for it. That's not a bad second option.
The Gazelle Web site offers to purchase several different types of consumer electronics equipment, including old digital cameras, and Gazelle will pay shipping costs for the unit. Visit the Web site, search for your device, and Gazelle will give you a projected payment.
Granted, you aren't going to receive much money, especially if the item is more than a couple of years old, but you'll at least have the satisfaction of knowing you've participated in the most effective kind of recycling program: Reuse.
Screen shot from Gazelle