makenmarketing

This plugin allows you to designate certain products in your WooCommerce store to have no price. Instead, it displays a configurable button for customers to request a quote directly via a chat app (like WhatsApp).
From the settings page, you can customize: 
* The WhatsApp phone number. 
* The button text and icon. 
* The predefined message the customer will send. 
* The button colors.

Quote via Chat Button

Replaces the "Add to Cart" button with a chat button for products without a price, with customization options.

Cristiano Zanca

wpnetworkit

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.

Discount and regular price cart and checkout page display WooCommerce

Display regular and discount price in the Cart

Quote via Chat Button vs Discount and regular price cart and checkout page display WooCommerce