This BigCommerce plugin enable your users to request a quote through your store’s front-end. An email will be sent with all the cart items to the store admin for negotiating prices with your customers. This is very easy to use add-on. Customer just have to click the “Request a Cart Quote” button and a popup will appear with all the products in the cart and user just have to give his name and email (if not logged in) to proceed.
To view demo, go to demo link below, add few products in cart and then go to cart page to view this add-on in action (Screenshot).