You may want to keep a closer eye on your mail. The envelope that looks like junk mail could have money inside.

Danette Bourne Allen found an envelope from PATH, the population assessment of Tobacco and Health, a program with the National Institute of Health and Federal Drug Administration, in her mailbox. It was addressed to the 'current resident' of the address.

Allen usually doesn't open junk mail. It normally ends up in the trash. "I was curious what it was for whatever reason," said Allen. And it's a good thing she was.

Inside the PATH envelope was an online survey that paid 5 dollars. "Regardless if you take the survey or not there is a real 5 dollar bill in It."

Credit - Danette Bourne Allen via Facebook

"So if you get this open it up," suggests Allen.

Nielsen sends mail to homes with invitations to complete short surveys on TV viewing and radio listening, or even to be part of the Nielsen ratings. Mail from Nielsen may include a survey that can be completed online, filled out and returned via mail, or done over the phone. All include money to compensate you for your time.

You may want to keep a closer eye on all your mail. You never know what could be waiting inside.

"Now I think and wonder if I tossed out any other money," said Allen.

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