It's official: Virgin Mobile USA will indeed begin selling the iPhone with contract-free, prepaid plans for as low as $30 per month for some users. The company made its announcement early Thursday morning on its website, offering both the iPhone 4 and iPhone 4S on its CDMA network licensed through Sprint.

As earlier rumors suggested, the devices will indeed be available before July rolls around—Virgin Mobile says its new iPhones will hit the streets on June 29. The 8GB iPhone 4 will sell for $549 while the 16GB iPhone 4S will go for $649. The tradeoff for those relatively high handset prices is the lack of a contract—users can pay as low as $30 per month for 300 voice minutes, unlimited text messages, and "unlimited" data—throttled after the 2.5GB mark is crossed—when you set up your account to autopay. (Without autopay, the plans are $5 more per month.) For $40/month with autopay, users can get 1,200 voice minutes with unlimited messaging and data, and for $50/month, they can get unlimited everything.

Virgin Mobile is the second prepaid cell carrier in the US to offer the iPhone. Cricket was the first to announce its plans in May, offering the 8GB iPhone 4 for $400 and the 16GB iPhone 4S for $500. Those up-front prices are lower than Virgin Mobile's by a good $149 each, but Cricket's monthly plans are higher—the company offers a $55 monthly plan with unlimited calls, texts, and data, with the same caveat that data speeds will be throttled after 2.3GB.

If you only use a handful of voice minutes per month and don't need unlimited calls, though, Virgin's $30/month plan will likely save you the most money—about $180 per year, which would make up for the extra $149 premium you'd pay for the handset through Virgin, and then some (especially if you stick around after the first year). Virgin Mobile's network has a wider reach than Cricket's as well, so there's a good possibility that some users might live in a market that only has one of these carrier options.

The lingering question is whether these prepaid carriers will offer the next-generation iPhone when it is announced (most likely later this year). If so, will any of you be ditching your contracts for one of these prepaid options, or will you be too drawn to the inevitable LTE support that will likely only come through Verizon and AT&T?