
For reference, every hero below the hero cap has zero maintenance costs.

It's possible to hire a hero without raising the hero cap, but doing so costs an extra 200 gold up front and 30 gold in maintenance per turn. However, players will also need to get a new city to raise the hero cap. That means the best way to raise the hero cap past 3 is to raise the city cap using the Expanded Governance rite in the empire development tree, a rite that every faction gets access to. Because of this, the hero cap is closely connected to the city cap.

Conquered and incorporated cities count, but outposts and vassals don't. Players can only have as many heroes in their faction as they have cities under their direct control.
