You may get a chuckle out of this ... my middle daughter actually did post an ad on Ebay to sell her little sister. Ebay pulled it within a day once they realized she wasn't trying to sell a series of books about sisters, but her actual annoying, little sister. A few years ago when I was cleaning out their room, I found a newspaper clipping. It was a classified ad form that the same daughter had filled out to sell her little sister. She never tried to sell her older sister, just the younger one. I still have that newspaper clipping stashed away. I have a younger sister, so I understand how she feels, but I got a great laugh out of it at the time. They are 18 and 20 now, with a 22 yr old older sister ... I hope they will appreciate each other more when they are older.