I think it be would best if you just get his frags to upgrade him to 4/5 star. You can get 26 of his frags and over time you should be able to get the other 80 and 4 star him. He's okay at the moment, good for Jinchuriki's but the only two we have are Naruto and Gaara. Regular Naruto is currently outclassed, thus you will want to use Sage, and Gaara is difficult to get to 3 star if you didn't recharge for him and didn't get the KazeKage Version. But if you're running wind main and have those two, then it's nice to have Killer Bee.
i have 4* gaara because i'm not really f2p i did recharge around 70$ for medal and some other stuff i want however windmain is the only class i don't have unlocked and i don't have sage either i just wanted to get him to have him for future use like an investment but i guess i could get him cheaper in other events.
Should i go for sage jiraiya frags instead only the free ones , i do have some more and after getting the free 28 frags i would have 41 frags so about have the needed amount or should i spent the points on keys