Does Mace Windu have to pay for upgrades that are acquired using his power action? "Look at the top 4 cards of your deck. You may play an upgrade from among them. Place the rest on the bottom of your deck in any order. If that upgrade was played on a Jedi, give it one shield."
I've noticed that other cards such as the Outer Rim Outlaw require you to pay ("Play a yellow card from your hand (paying its cost). Then reroll an opponents die or reroll up to three of your dice."), but Mace's text doesn't say anything about it.