Accrue at least fifty shotgun shells before starting a new run. To save ammunition, early in your run you can easily avoid zombies instead of shooting them. Jump over or avoid them to progress. Although some zombies may drop extra coins and power-ups, you will not need them that early, and your ammunition is more important. After you reach the 10,000 mark, you will need all the ammunition available to clear the masses of zombies. Only purchase the biggest box of ammunition. You can get 200 ammo for 3,000 coins, saving 800 coins over the 50 ammo pack. The more you purchase, the lower the cost.