QB Issue Resolution:

Okay, I believe you need to contact QuickBooks support to discuss this with you clearly. They may have discounts or good offer for adding user-licenses and they can also process it easily on their end. Here’s how to reach them:

https://help.quickbooks.intuit.com/contact

Select your QuickBooks version.
You need to select a topic or you can click on “Other” for topic and type in your issue on the right pane.
Click on the Phone button to show you the number of support.

Resolution for Issue 'I tried to go to manage my license but I do not have the option to add users. What is the cost of adding an additional user?' available: Yes (Solved).
Source: Intuit Community forum.

I tried to go to manage my license but I do not have the option to add users. What is the cost of adding an additional user?: this issue or error code is a known issue in Quickbooks Online (QBO) and/or Quickbooks. Support for this issue is available either by self-service or paid support options. Experts are available to resolve your Quickbooks issue to ensure minimal downtime and continue running your business. First try to resolve the issue yourself by looking for a resolution described below. If it is a complex issue or you are unable to solve the issue, you may contact us by clicking here or by using other support options.

Support for Quickbooks
Quickbooks Repair Pro will resolve it efficiently and affordably. Guaranteed resolution of your issue, or you pay nothing!

Error Recovery for Quickbooks [Canada]
E-Tech is the #1 Quickbooks data migration and Conversion service provider.

Get 50% off Quickbooks Online

Click Here for 50% off!

Additional Support Options: