Yupz! As stated above, the monthly 300 ingots and Jonin Medal would be the best way to utilize ingots. Other ways that can help you is to make sure to recharge during a rebate and spend ingots during a rebate. Stacking the redeemable prizes you can earn on top of what you were actually looking to do or get is always the best option!

~Jib

P.S. You guys are great XD Always giving such great answers before I can T_T Love it!