The market for Coca-Cola advertising pieces is one of the largest collectible markets in the world, says collectibles expert Harry Rinker. A Coca-Cola Barbie Summer Daydreams sold in April for $39.99 on eBay, and a set of five vintage Coca-Cola trays fetched $300. Aside from the recipe for Coke, a closely guarded secret, a prototype Coke bottle may be the most valuable bit of Coke memorabilia: One sold for $250,000 in 2011.
