If you have a smartphone, check out the CoinOut app.
This is a super simple, no strings attached app that lets you snap a photo of your old receipt and get money for it. You can get anywhere from $.01 to $.20 per receipt and you can currently take pictures of about 5 receipts per day.
It might not sound like a lot of money, but there is no minimum to cash out your earnings to your PayPal account. Also, the company, which was featured on Shark Tank, is hoping to offer new features into the app in the future, increasing the potential to earn even more rewards.