If you're using Magento 2, Then I would recommend to you use Request For Quote by Solwin.
Why this Magento 2 Extension?
This Magento 2 quotation extension allows adding a price quotation feature into Magento 2 store. This way customers can easily negotiate the price using a quick quote system. The module will let users bargain right on the website and prompt them for bulk purchases with the best prices.
By clicking on ‘Request for Quote’ customers can request a quotation for a particular product. The customer has to fill up the requirement form with all the details.
Benefits Of Request For Quote Magento 2 Extension,
Hope it helps!
I know a right solution for your demand, please explore this module: Magento 2 Quote Extension, and try the demo for better understanding how it works.
The module allows both guests and logged-in customers to submit request for quotation forms on product pages.
Customers can add multiple products to cart and quote with desirable price. If the store admin agrees with the quotation, they will convert that cart to an order and customers can place order and checkout.
Here are some highlight features that you may be interested:
Hope my suggestion help you out!