On the Reveal phase of a round when a Hit is played, it can be executed immediately in the Reveal phase, or it can be banked for later use.
A banked Hit can be used in the Money Talks phase of any round, including the round it was played in. (However, a banked Hit can not be used in the Reveal phase of a subsequent round.)
A player using a Hit, in whatever phase, must spend three Money. A player with insufficient Money may not use a Hit.
Once used, in whatever phase, a Hit is discarded.
Rarely, Crime and Hit in the same stack can be in conflict, when a Crime would reduce a player’s Money below the three needed to pay for the Hit. When this happens, the Crime takes precedence and the Hit can’t be used that round.