public void Sell()
{
if (CurrencyManager.Instance.CurrentCurrency() >= cost)
{
CurrencyManager.Instance.RemoveCurrency(cost);
GameObject newGun = Instantiate(gun, shopCannonBarrelEnd.position, shopCannonBarrelEnd.rotation);
shopCannonBarrelEnd.GetComponentInParent <ShopCannon>().Shoot(newGun);
button.CloseShop();
}
}