What's the most interesting pricing you've seen for collaborative tools?

I've been studying collaborative tools (mainly productivity tools) pricing and business models. The great majority of them are per user/member, which I think can be a barrier for scaling to the buyer. Before the buyer even uses the product and get value from it, she/he is confronted with its cost and onboarding a new user will always bring the thought "shall we/we have to buy another seat" and will necessarily entail an increase in cost. Some interesting models I'm considering are: - no or little limit on the number of seats but pricing by folder/project/workspace. This way, the buyer is encouraged to get people on the tool and he/she will upgrade only when necessary ie. once they get value from the tool and they need more organization and private spaces for different teams. - a high limit on the number of elements used. I see this model mostly in whiteboarding tools where you can have fun filling out your whiteboard with thousands of elements for free, and then, for the 3001th element, you have to upgrade. What about you? What's your opinion on these strategies? Did you come across a compelling pricing model that would encourage the buyer to upgrade while allowing him to get plenty of value beforehand?