Hi, PrashantGJ. Given that Zotero is openly licensed under the GNU Affero General Public License (version 3), there's no question of getting 6 licences of Zotero for professional use.
And given that installing Zotero desktop is a one-click process, I doubt that there are people who charge for merely installing it. There are plugin developers to whom you can donate.
You can, however, pay to get storage on Zotero.org and help in its development:
Upgrade Storage
And given that installing Zotero desktop is a one-click process, I doubt that there are people who charge for merely installing it. There are plugin developers to whom you can donate.
You can, however, pay to get storage on Zotero.org and help in its development:
https://www.zotero.org/storage/institutions
You can get involved in other ways as well:
https://www.zotero.org/getinvolved/