Zid will not charge you anything. However, the revenue will be shared between Zid and you, which will be discussed and signed with the partnership agreement after sign-up.  

There are 10 available categories:

1. Inventory Management

2. Accounting

3. Analytics and Reports

4. Shipping and fulfillment

5. Operations Management

6. Drop shipping

7. Customer service

8. Marketing

9. Productivity

10. Payments

There is no limit,  you can create and publish as much as you want. However, for each Service, there should be only one App, and if you have another service you can use the same account to create another App for that service, etc... as well as the agreement, you have to sign one agreement for each App.

This is available only for enterprise-level partners. Therefore,  if he isn't, you can ask the merchant to upgrade his plan to get this feature.