It's free on IOS and Android, but they have ads for the developers to make money. You have to pay for the PC Version because there are no ads, and you get all of the skins and hats without having to pay extra.
LIES! When I downloaded it, I didn’t even get all cosmetics. I got all the hats, some of the skins(polus and Mira HQ not included), and no pets. The reason why is because pets are optional(meaning if you want them, you have to buy them). Also, the hat cosmetics normally on mobile(iPhone and Android only) aren’t even on PC somehow.