There is a feature in the odoo purchase module called "vendor pricelist," which allows you to provide a list of acceptable prices for a certain set of products and suppliers. If you specify a vendor and item in a buy order or request for quote, the system will use the pricing information from the pricelist that corresponds to the two.

Hi,

in odoo purchase module you have an option called " vendor pricelist ", you can set vendor pricelist for vendors and products. choosing vendor and product in purchase order/ RFQ it will automatically applies that particular pricelist. 

For further details please visit this link

https://www.cybrosys.com/blog/vendor-pricelist-management-in-odoo-15-purchase-module

Regards