While the deck itself is free, AnkiHub costs money. AnkiHub has multiple full and part-time software developers dedicated to improving and maintaining the software in addition to regularly adding new features.
Please consider the average price of a textbook and how much content is in this deck. We pay multiple people and have 100+ volunteers that help update and maintain the deck. If the price of AnkiHub is not worth it to you for the updates, you are welcome to use older versions of the deck or other shared Anki decks.
While we initially relied on donations to help fund the deck updates, it is a much larger project now and donations aren’t able to cover the costs associated.