We're big fans of fair billing at Lago, especially when it comes to 'per seat' pricing. Have you ever paid for 'seats' no one uses? It's been a common practice among SaaS for the past 10 years to bill for this. Luckily, some companies, like Notion and Slack took a different approach: only billing active users. This typically helps spreading the tool within an organization (anyone can be invited to test). The only downside is it can hurt short-term revenue (typically billing for unused seats is still a source of revenue), but our conviction is that it helps with long term trust and growth (at some point the users will remove unused seats anyway, and be resentful).
So we've done a teardown of Notion's fair pricing, and how they incentivized product discovery through a credit system.
We also had a lot of fun showing how our own product could be used to replicate that easily [1].
FYI, we build "Open Source Usage Based Billing" (AGPLv3) [2]
[1] https://www.getlago.com/resources/templates/notion
[2] https://github.com/getlago/lago