Hello! Please forgive me if this is in the wrong place or if its been already discussed. I was looking around at Yo-SD four sisters on second hand markets and realized that certain sisters seem to be more expensive. I heard that Megu was the most valuable (I'm not sure if that's true). I was curious why (though they seem to be the same headmold) the price of one sister is greater than another and if that's true. Can anyone explain it? Thanks!