Apple braces for court fight over what's the fair price for an iPhone app

iPhone users accuse Apple of violating federal antitrust law by monopolizing the sale of paid apps, leading to inflated prices compared to if apps were available from other sources.

When iPhone users want to edit blemishes out of their selfies, identify stars and constellations or simply join the latest video game craze, they turn to Apple Inc's App Store, where any software application they buy also includes a 30 percent cut for Apple.

That commission is a key issue in a closely watched antitrust case that will reach the US Supreme Court on Monday. 

The nine justices will hear arguments in Apple's bid to escape damages in a lawsuit accusing it of breaking federal antitrust laws by monopolising the market for iPhone apps and causing consumers to pay more