You have an minimum amount to spend , for example the most easy is tendo , you get rares between 40-80 seals for any pain/sage jiraya/beheding kakashi, the average is 60 seal for one rare , for hashirama/tendo ,which are super rare ,is at least minimum between 360-420 from what I heard and know, if you got any of them , you will have to spend again at least 360-420 to get any of them again

Also I advise you to not spend on kage treasure now because it is bugged , if you just want to understand how it works , there are videos on YouTube with pulls on every treasure and you will see what I am saying ,

example :

https://www.youtube.com/watch?v=HBUB3WElN0k

If you don t want to spend on money on the game , You can try your luck with 10 scrolls more, 10 scrolls you can take from free draws , that takes 20 days, start to count the free draws , after you made 10-11 , spend 10 seal scrolls so you will get the rare, the best you can get is Ningedo or Jikudo, also Shurado on 1.0 is good with fire, If you are still on 1.0 , Yea keep for kage, is the only one worth, Also Sage Naruto from Sage Treasure is worth but there is a lot of gamble , can cost 60 seal or 180 , the rare there are Ao , Sage Naruto and Konoha Traitor, for me cost me 180 seal I did not have luck