You can get coupons from the daily sign-in(seals also),wishing tree,online pack from the benefit hall,convoy and plunder,9tails invasion,ranked/spacetime when you reach certain ranks,some events like the myoboku trial,lucky *,and wheel of fortune have coupons in them(seals also and i think are the only events that have coupons in them.The lucky stars wheel and the great plates event gives seals),lucky wheel in the group base,summon capture,kakashi ninjutsu trial,anko's ninja test(there's a chance of 20 coupons),konoha's ninja puzzle(there's a chance),lucky board has 5 coupons,when you recruit a certain amount of ninjas,you can get 50 coupons,the bond level ninja thing in "Home" which some ninjas gives seal frags,there's a chance survival gives coupons and seals (so far,i've gotten 10-30 coupons and idk how many seals),and the cat quiz gives coupons.Great Ninja War packs,when you do sealed ninja(there's a chance),and "Monthly Event" gives seals too,if you go to "Space Time",then go to "Strongest Ninja" and click on "Redeem",that little shop gives seal frags which you can only get 1 frag per day for 5k bet chips.The weekend events gives coupons and seal scrolls too.