We'll create fresh WordPress site with Discount and regular price cart and checkout page display WooCommerce installed. You have 20 minutes to test the plugin after that site we'll be deleted.
By default in the WooCommerce Cart page is only displayed the discount price, using “WooCommerce Discount and regular price plugin” is displayed also the regular sale price, so your customer remember easily the discount amount.
At the end of the cart and of the checkout page diplays the total amount of money you saved with discounted price.
Thanks to Rodolfo Melogli, Bülent Sakarya, Daniel Pataki, Scott Bolinger