5. Slidejoy

The concept of Slidejoy might seem a little strange, especially if you are quite particular about how your smart phone looks and is laid out. Slidejoy basically changes your phones lock screen to an advertisement, which you can choose to either ignore or click onto, doing either still generates the same amount of money.
You aren’t going to become a millionaire using this app, but it’s a good way to make an extra $20 or so a month.