Yeah there is as far as I know (I've You Tubed it). You can buy moons? Like the skipping rope one or are they separate have to buy moons?
The moons that you bought aren't any moon on the moon list. They just adds up to the total number of your moons on the Odyssey. And I don't think you can reach 999 without buying moons. So that's what I'm gonna do in order to discover the hidden ending.