From Binary Options Wiki
In binary options trading, a successful investment would come in the form of an in-the-money result, earning you a healthy return. For example, let’s say that you purchase a $300 Call option of stock XYZ because you heard that it was doing well and is on the rise.
This particular stock offers a 70% return on all in-the-money results and the price currently stands at 2.0972. As predicted your informed decision pays off and the stock finishes at 2.0978. This successful investment leaves you with a pay-out of $510 ($210 of the 70% return and your original $300 premium back).