PHILADELPHIA - Pizza chains have renewed their battle for a bigger slice of pizza sales, the Indianapolis Star reports. Pizza makers like Domino??s Papa John??s and Pizza Hut are using new recipes, lower prices and mobile phone pizza ordering apps to revitalize business.

"They are intensive competitive marketers. They??re going to try to mimic each other and one-up each other's offerings, whether they're competing on quality of ingredients and formulation or the latest deals," said Nancy Childs, professor of food marketing at St. Joseph??s University.

Two years ago, Americans shelled out nearly $38 billion buying pizza, although that number remained the same compared with 2008. Pizza chains are stepping up their game with new campaigns designed to boost sales.

For example, Little Caesar??s debuted its Pizza! Pizza! Pantastic, which features one pepperoni pizza and one supreme for $9.99. Papa John??s has a free app that allows consumers to order any menu item from anywhere.

Pizza Hut had a $10 special for any pizza, any way. The most extreme example is Domino??s complete revision of its recipes ?" that move garnered more sales for the company.

Pizza has lots of appeal to consumers, especially in a tough economy. The popular pie is expanding its customer base beyond the traditional Cub Scouts, college students and cheapskates. "This is a good value meal, and people are looking for that," said Childs. "If people can??t afford a restaurant out, they can still afford the pizza to take them out of the kitchen. This is the time when you're looking to expand your market share to get more customers, so it makes it even more intense."