I wouldn't waste my money on seal scrolls. Almost every single ninja you can get from scrolls will be available in a month from shops. Four of the Pains, Konan, Itachi, Zabuza, Kakashi, Asuma, and the ones like Orochimaru/Jiraiya/Tsunade are farmable from instances after Chapter 8.

Likewise, there will be a place in the future to get tons of refining tools. But you can spend your free coupons to get some of those.

Instead, use your gold only for Stamina and possibly spinning the lucky wheel. That's 10 ingots each. You c*so use it to donate to the group if you want quicker stats and a faster group level up.

So you're only spending 10-20 ingots per day and save the rest for next month or so when new stuff comes because it's going to require a ton of ingots to get the awesome ninjas.