In some product categories, we can see that variable pricing has been made into a reality. One such category is pineapples, where you can pay $0.16/oz, $0.30/oz or $0.55/oz, depending whatever you're willing to pay...
Pineapple Organic, $4.99 / ea (weighing 30oz) => $0.16/oz
Pineapple Cored, Del Monte, 20 oz pkg for $5.99 => $0.30/oz
Pineapple Spear Single, Del Monte 2.7 oz pkg for $1.49 => $0.55/oz
Prices and products from Peapod.com