Personally i think this is the best event to use coupons or ingots! Overall u can get so much! lvl 4-5 manga from lucky box, seal scrolls, summoning scrolls , mood scrolls etc. This is so good for overall raw power! The ninjas are nice this time also but i understand the f2p part, but overal u never know also if u can be lucky and get a ninja like itachi/jugo/hashirama with luck/rng. Obviously its up to u :P