Hello,
From what I know price for Start11 is as mentioned here : https://www.stardock.com/products/start11/download or for Curtains 11, there is no official announcement on it yet.

Thanks
Basj,
Stardock Community Assistant.

@basj

There is an upgrade pricing options but it appears to be broken.  If you type in your email address it does not see you have stand alone seats if you have an Object Desktop license.   If it does not work properly as they are aware of in this other thread I found on the forums then they should remove the link from the website till it is resolved.

@sdrohan

You are already aware of this issue.  You even commented your team is having an issues with resolving it in this thread. 

https://forums.stardock.com/506423/page/1/#3815610

I choose to buy separate licenses for each machine as I want to support a company that provides what I consider a valued product and since 4 of these computers are not under my roof.  I can wait till you sort out the issue.  I also believe that the spirit of the license is one per each machine.

Not sure when you tried but it is working with the email address you have for your account:

Sean Drohan
Stardock Support Manager

Quick update.   When I closed the tab i had open making the previous post.  The tab I was using for screenshots I noticed had something in the shopping cart.  I saw Start11 for 3.99 so I purchased 7 upgrade licenses.  While it did add it to my cart and I was able to purchse there is some confusion still on what it displayed when you press get it now.  Thanks for getting it fixed enough to purchase the software.  Looking forward to Curtains compatible with Windows 11 soon.  Keep up the great work and thanks Sean.