The YITH Request a Quote for WooCommerce plugin lets your customers ask for an estimate of a list of products they are interested into.
Plugin extends WooCommerce by outputting "Call for Price" when price field for product is left empty.
The WPB Request a Quote for WooCommerce plugin shows a Contact Form 7 popup on button click. It lets your customers ask for a quotation.
A Feature-Rich Plugin (aka Extension) for Dynamic Control to Show/Hide Price or “Call For Price/Quote For Price” Button
Allow your customer to add products to Quotation Cart and ask for price or any information regarding the order by submitting a Quotation form.