I am still waiting for games to pick up this idea from 2009. Achievement systems have proliferated, tracking all kinds of things, but most games want to give you cosmetic items instead of unlocks. One specific item in that last post has been addressed by many games: a mount tab instead of making you carry mounts around. City of Heroes has always rewarded players by unlocking costume pieces, and Borderlands 2 lets you find/win/buy customization options.
With the upswing in F2P, however, life moves in the opposite direction. Storage space and cosmetic customization are ways they make money, so of course they charge you per item per change in appearance.