I like the idea of having a wand core re-roll, but considering that it doesn't affect much in the game, is it worth having it at all in the store? Other players aren't able to see what type of wand core or wood another player has, so I don't think it would be worth much. Maybe it could be free every month just to satisfy a player who doesn't like their wood/core? Or possibly create an in-server shop area that lets the player choose their wood/core for gold instead?