You do know that you get the skin from somewhere, aka someone has to spend real money for them in the 1st place.
Few months ago, I made a really idiotic decision of me spending real dollars on skins (no, not from those nasty RWT’s) and sold them 1 Deca each, and I ended up selling Decas for 2 Lives each. Think about this, spending few hundred Realm Gold for a skin and then selling converting those Decas to Lives like that, it was a heavy blow to my dollars and to my RotMG experience to the point I would never do it again.