Slayground by Richard Stark

Parker and associates knock over an armored car, but the driver of the getaway car screws up. Parker grabs the loot and runs into an amusement park that’s closed for the season. He stashes the money and then tries to avoid being caught by a gang of local criminals and two crooked cops who know he’s in there with all that cash. Parker escapes but has to leave the money behind (for now).