Easy Digital Downloads is a wonderful plugin that lets you sell products on your WordPress site. There are plenty of free and premium extensions available for it that let you add more features to your online store. Easy Digital Downloads Points and Rewards is a handy plugin that lets you reward your customers for purchases that can be redeemed for discounts.
The plugin encourages your visitors to do business with you and come back for more. You are in control of how points are awarded and the amount each one is worth. It is also possible to reward customers for signing up. Users can also see a log of all the points earned.
This is a paid extension for Easy Digital Downloads. You can find out more about it here.