Don't have a 3D printer at home but want the custom goods it affords? eBay can help with its new iOS app eBay Exact, which allows shoppers to buy their own 3D printed objects from companies like Sculpteo, Hot Pop Factory and MakerBot. For now, shoppers can buy about 20 different items, tailored to their liking, from iPhone cases to figurines and jewelry, at a price of$9 for the former to $350 for a metal ring.