Apple's much-rumored budget iPhone will reportedly sport a 4-inch Retina Display, plastic casing, and will come in a variety of colors similar to Apple's iPod lineup.

While Apple refused to enter the low-cost market in the past, repeatedly claiming that it will not compromise its device experience to hit a certain price target, recently it became apparent that a low-cost iPhone would work wonders for the company. Apple could reportedly add as much as $11 billion to its annual revenue by making an iPhone available cheaply to pre-paid customers in markets such as India, where subsidies are not an option. The move would also help the Cupertino giant grab some additional market share in markets where Android is currently enjoying wild success.

AppleInsider learned the details on Apple's so-called budget iPhone from KGI analyst Ming-Chi Kuo, who has a reliable track record in predicting Apple's future product plans. Kuo's predictions proved to be spot-on several times in the past, including predictions about the iPhone 4S release timeline and changes, the launch of the original white iPhone 4, as well as the iPad 2, among others. Now, the analyst is telling AppleInsider that the low-cost iPhone will sport a 4-inch Retina display like the iPhone 5.

According to Kuo, the specs for Apple's budget iPhone were decided in 2011, and the Cupertino giant is "unlikely to abruptly change" due to a market shift toward bigger displays in the 5-inch range.

"Contrary to some rumors suggesting Apple's low-cost iPhone will have a larger 4.5-inch display, the company's new entry-level handset will have a 4-inch display, matching the size of the iPhone 5," AppleInsider reports.

The new, low-cost iPhone model will reportedly feature a "super-thin plastic casing mixed with glass fiber." According to Kuo, the material will make the handset stronger, thinner and lighter compared to typical smartphone plastic casings.

Kuo further predicts the handset will come in a range of colors, much like Apple's iPod lineup. The analyst says the budget iPhone will be available in between four and six color options, expanding from the current black and white choices currently available for existing iPhone models.