At a time when smartphone world is filled with the buzz of Apple's upcoming next generation iPhone 5, the predecessors of the same device, iPhone 4S and iPhone 4, are being offered by the U.S wireless carrier operator Virgin Mobile as prepaid handsets.

The operator recently announced that the 8GB iPhone 4 will be offered at a cost of $549, while the newer 16GB iPhone 4S will cost $649 with no contract.

Both handsets are now available for purchase and will come with Virgin Mobile's unlimited data and messaging plans that start as low as $35 per month. Apple's smartphones are available through Virgin Mobile's website, RadioShack, Best Buy and select local retailers.

At the same time, regional carrier Cricket, owned by Leap Wireless, was the first carrier to offer a prepaid iPhone in the U.S. The company is still offering users 8GB iPhone 4 at $399.99 and the 16GB iPhone 4S for $499.99, besting Virgin Mobile's hardware pricing by $150.

Hence, customers looking to ditch their current contracts and purchase an iPhone commitment-free can take advantage of this new Apple-Virgin Mobile partnership.

Upfront, customers will have to shell out almost $700 for an iPhone 4S that normally costs $200 on a regular carrier with a 2-year commitment. But when it comes to the monthly service, pre-paid can save people almost $60 per month as Virgin Mobile offers unlimited data, talk and text for just $55.

However, Apple may possibly planning to offer its loyal customers a bigger bite of smartphone experience with its next iPhone 5, as claimed by industry watchers. Recent rumors have reportedly suggested that the next flagship model by the Cupertino giant may get released as soon as September with a combination of revolutionary hardware enhancements and software-driven services such as Passbook, Maps, FaceTime and more.

Apple's sixth generation iPhone is reportedly expected to feature 4-inch Retina display, an A5X Variant chip, 1GB RAM, iOS 6, 4G LTE technology, Near Field Communication (NFC) technology, improved Siri, an 8 megapixel (or even higher) rear-facing camera, a 2 megapixel front-facing camera for video chatting and an improved battery life.

Other rumors suggest that the next iPhone will have a smaller 19-pin dock connector instead of the typical 30-pin connector, a new Liquidmetal casing and will definitely be a Samsung Galaxy S3 killer.

Last week, Terry Gou, the CEO of Hon Hai (parent company of Foxconn) told China Times newspaper that the iPhone 5 would put the Samsung Galaxy S3 to shame.

So what do you think? Are you interested in buying the new prepaid versions of iPhone 4/4S or will you wait for the Apple's heavyweight, the soon-to-be-unveiled iPhone 5?