Provides a admin view for managing alll promotions for a product. also provides a formatter for showing discounted price, actual price and savings off.
after enabling the module, Go to http://your-domain/product-discount-view and select active for a product and then enter discount percentage and then click save.
Go to admin/commerce/config/product-variation-types/default/edit/display and enable disocunted price formatter for the price field.
now you can see your prices, saving off on your product.