No, I'm not talking CVS ExtraBucks here. We're talking about actual cash. If you're interested, you should look into being a mail tracking agent. No, you won't get rich doing it, but it's a little extra pocket money, and you'll probably get some great free magazine subscriptions along with other interesting mail, too.
Basically what happens is you receive test pieces of mail sent to you. You'll be able to distinguish it from your actual mail by the names that are used on it. The company will provide you with a website where you will key in details about the mail, and then you will be asked to store it for a short period of time in case the company needs additional details. Occasionally you may be asked to return a piece of mail back to the company, and you will be reimbursed for this. They only need a handful of people in each zip code, so it may take some time to hear from them.
I know of two companies that do this:
I don't have any experience with U.S. Monitor, but I've been doing this for Hauser for about five years now. They pay 25 cents per entry, and it takes 30 seconds at the most to key in a piece of mail. I get approximately $30 a quarter, but I also get some really great high-priced magazine subscriptions, like Time, People, Entertainment Weekly, and Sports Illustrated. It started out pretty slowly, but as you prove your reliability, they start to send more mail. I've actually had a fairly significant increase since my last check, so I'm anxious to see how much my earnings have increased.
Please let me know if you have any questions, and I'll do my best to answer them!