Boo yah! Double meaning-ed AGAIN. Ok that wasn't a ""double"" meaning.
So what kinds of things can you spend Aces on?
Now this is not an exact list but rather a vague list.
So firstly, some combat maneuvers:
Laying down cover fire
Move your opponent two yards
Knock your opponent Prone
Make a second attack
Disarm your opponent
Move yourself to the top of the initiative
Now some non-combat uses:
Calling in a favor (Lets say the party needs horses, a party member might spend 3 or 4 Aces to say that they have an uncle in town that owns a stable and can give them a good deal)
Move an NPC 2 yards
Impress an NPC
Take another action immediately following your action
Make a prediction (Ask the GM a simple question about a situation such as, “Who here would be easiest to provoke in a fight?” and for the rest of the scene the answer the GM gives is true)
So all of these will have a set Ace cost, except Craft and Favor which will have a variable cost depending on how complicated the item or how powerful the favor is.