While "Transformers Prime" is not typically available for a permanent free download, you can stream all three seasons and the "Predacons Rising" movie on several platforms:
As he clicked on the link, the terminal suddenly sprang to life, and a holographic display flickered on, revealing a menu of all the episodes of Transformers Prime. Jack's eyes widened in amazement as he realized that he had stumbled upon a treasure trove of Autobot adventures.