What are the free CMS or CRM plugins for customer sales/purchases?

Question

CMS

There are customers who can sell a product and buy another. Tell me, please, is there a system where you can create a card for customers and assign to him the goods that he wants to buy, and the goods that he has for sale?
Maybe there are CRM plugins for CMS like Wordpress or something else?

p/s/ You don’t need a store, but only a backend with a kind of CRM system, where you can create a customer card and indicate which goods he wants to buy and which he wants to sell.

Answer 1

For WordPress there is WooCommerce

Answer 2

In fact, you need an online store with the ability for users to sell their products.
I see 2 options for solving the issue:
1) Woocommerce + Multivendor for Woocommerce (a bunch of plugins for implementing multivendor)
https://ru.wordpress.org/plugins/dokan-lite/
https://wordpress.org/plugins/wc-multivendor -marke...
2) Second option - https://wordpress.org/plugins/classified-listing/
Just buy the premium version ( link ) and then you will have this functionality Shop
Or you can always take a framework and write your solution from scratch

Answer 3

codecanyon.net/item/cqpim-wordpress-project-management-plugin/11788321

Answer 4

Bitrix24, if only CRM is needed. Even on the free plan, the functionality is extensive, plus a powerful Rest API, which can partially replace the robots available on paid plans.