Imagine what would happen if your childhood best friend turned all pricey? At least Barbie will as she gets new best friends in form rare pink diamond necklace signed by Stephen Cantur. Though our favorite doll is still the same, its the pricey necklace that has shot her to fame in the luxurious world. And with this move, she becomes the most expensive Barbie till date commanding a price of $550,000 dollars.