Moon scrolls you get from arena,bonds,TI,ranked,space-time,weekend sage and matsuri,3v3.

Seals you get from survival,sealed ninjas,GNW packs,sage and matsuri(if can win),sign-in.You probably can make 6-8 seals per week,so 600 will take you quite a while.You best choice is to save 300,and use at rebate,it will bring you 60 seals back.