This is pretty self explanatory. But I'm not sure as of yet if the new season will award you with legendary stuff as you rank up but for now the only way to get legendary pieces is to buy them from the store with your crowns. Costume pieces cost 5 crowns a piece, 3 crowns for patterns and 2 crowns for the colors. I believe you can earn up to 3 crowns just ranking up to 40 but mostly you will have to win episodes to earn them.