Every skin here exists once on the whole server. Buy it and it is yours: nobody else has one like it. The ones that already have an owner are marked.
Why they all cost the same
What makes a skin worth having is that it is unique, not its art. Charging more for one than another would say the rarity is in the picture, when it is in there being only one. The lucky box in the game draws them all with the same odds for the same reason.
The game did not say which skins are free. To be safe, nothing can be bought until it does.
No skin matches that filter. Try another kind, or show the owned ones too.