Most effective use of coupons and ingots for increasing power

like what crafter said you could do those things but you could also go for Mt. Myoboku because that made my Power go up by about 1,000. Also you can get the Battle Armer to rank 9 and try to get the new costumes that raise power and other stats.

Firstly do upgrade your magatamas to level 6 so they would help you out and if you want to use cool ninjas then waste your coupons and ignots on some really awesome ninjas like naruto (kurama mode), ay(fourth raikage) gaara(fifth kazekage) or then five members of pain.

If you got 3 in your team then make sure you have tendo for summons, and you can decide the other 2 for combos or u can use anyone else than pain, but first make sure you have at least a level 5 or 6 magatama in every field like health, attack, etc.