MONOPOLISTIC COMPETITION...!!!!

Monopolistic competition is a situation where the product can be differentiated to allow the providers that opportunity to charge premium pricing for their product, which has imperfect substitutes. Firms compete by selling differentiated products that are highly substitute-able for one another but not perfect substitues. In other words, the cross-price elasticities of demand are large but not infinite. There is a free entry and exit. It is relatively easy for new firms to enter the market with their own brands and for existing firms to leave if their products become unprofitable.
The perfect example is the monopolistic competition in the markets for Colas.

A brief frame of how the monopolistic competition model is.

Note that among colas, Royal Crown is much less price than Coke.

Royal Crown Cola

Although Royal Crown Cola has a small share  of the cola market, its taste is more distinctive than those of Coke, Pepsi and other brands, so consumers who buy it have stronger brand loyalty. But even though Royal Crown Cola has more monopoly power than Coke, it is not necessary more profitable. Profits depend on fixed costs and volume, as well as price. Even if its average profit is smaller, Coke will generate more profit because it has much larger share of the market.

http://www.bladeforums.com/forums/showthread.php/344045-Coke-vs-RC-Cola