If you are looking for the best price, official third-party stores often offer Steam keys at a lower cost:

Additional DLC, such as Ancient Beasts and The Mechanist , is available for purchase to expand the endgame and add new classes. Pricing and Legitimate Discounts

The complete experience, including all five acts and infinite character progression, can be purchased on Steam, GOG, and the Humble Store .

Available on GX.games, this version includes all five character classes (Templar, Berserker, Warden, Warlock, and Mechanist). Note that save data from this version cannot be transferred to the paid PC version.