Hi @Khrystyna - welcome to the Community!
It sounds like you're looking for a non-profit discount for Trello. I've raised a ticket on your behalf for you to chat with our billing and sales team about this, this ticket is CA-2193662, and you'll receive all updates about it via email.
In the meantime, you're welcome to try a 14 day free trial of Premium at https://trello.com/free-trial
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