Save your coupons, wait for events like Sage with 30-40% off refines/threads/mood scrolls, then further wait for a rebate event for another 10%+ in returns. You're looking at 40-50% off savings by planning ahead and your ableness to resist not using up your coupons till these events come around.
I'm sitting on a stock pile of coupons atm, waiting for a large discount event such a Sage, and I also stockpiled a ton of medium refines, and advance refines as well as medium threads waiting for a rebate event. It's tempting to use up these supplies to get a early start in the power gain but planning ahead, waiting is the wisest.
Unless we get some sort of new event, Dice has got to be the best power:ingot/coupon spent ratio. Next is prob lucky wheel, and as for the others like lucky stars or treasure chests, etc they're purely no power gain for ingots/coupons spent.
*source - S177 #1 power ranking, but not the heaviest spender
This post was last edited by ber***@hotmail.com at 2016-12-20 18:51