Could you play the same action more then twice in a turn?

If it doesn't have a trigger, like "beginning of turn" or "when a unit is healed" then you can play it as many times as you can pay the cost.

There are only a few actions in the game that are limited to once per turn. Such as the ancient waystone. And that action would be once per turn, per card. So three waystones can do one damage once per turn.

err, three damage total if you had three waystones out.

This is why the Repeater Bolt Thrower is so good.