The Silver Earring is the best accessory to use (only one player needs to equip it) since each barrel shot drops a $100 ingot. The Holy Earring is too random to be helpful. You can "conserve" money by buying the Silver Badge first (sold items give 20% more money) before buying the Member's Badge (items cost 10% less money). This helps when trying to buy expensive weapons like the 92.5% Silver Bullet.