Free teams on Trello will be able to use only up to 10 boards
help.trello.com
help.trello.com
On top of this, the price isn't remotely competitive. 30-50% of an O365 license, for a single application.
I realise they are cutting the deadweight off the platform and can at least appreciate that you get to keep the boards you already have. But when you are using Trello with a small not-for-profit org and the budget for online task management software is $0 then you can see where this is heading. Google Sheets?
We can install some open-source analogue like Wekan or Taiga but that then requires monitoring and updates.