When you get it always plan ahead on what you are going to spend it on. Use it to get some rewards from some events, and if Visored Revenge is up you get more rewards just for buying stuff. So planning ahead and being Frugal will really help you out in the end.
Wait do you get 188,888 coupons for 365 days? Thats a lot! And in terms of your question i would go for stones. On visord revenge so you get to spend it and get a lot back plus some goodies