When you have access to Ammu-nation, head to the back of the store to try your hand at various shooting range challenges. Take the time to score Gold ranking on all of them to earn a 25 percent on everything in the store for the rest of the game! Silver ranking meanwhile will earn you a 15 percent discount, while Bronze rewards you with 10 percent. Note that the discount only applies to one character, but you can earn it for the other two getting them to score Gold on the challenges as well.