I never understood the method of how they chose the amount to give you per mystery stone. Ill get 500 moons for ranked but it only gives me 7 mysteries, then the next day I'll get 200 moons and it'll give me 3 mysteries, either bump up the amount given to make it half of the moons given or cut the costs to not make it impossibly long to grind for some mediocre rewards and some fairly different cosmetic items we don't care about. Just doesn't make sense to me to even save to get them, or try to get them for different stuff, its worthless.

I know from being there long enough to know that the 3rd clothing item (the much more expensive one) was recently added a few months back because for a very long time there was a lack of new strange stone reward. So I guess the idea was that many people had an excess of stones / they just decided to add 1 item with crazy price so people won't ask for new things again for a while lol. So I'm guessing maybe the other item prices are also the result of something similar where one got implemented first and one got added in later.