Cultist Simulator  is available at $6.99 / 6.99€, and you can also buy DLCs directly in-game: 

• The Exile : $5.99 / 5.99€
• The Dancer: $1.99 / 1.99€
• The Priest: $1.99 / 1.99€
• The Ghoul: $1.99 / 1.99€

A DLCs bundle is available for $6.99 / 6.99€