For Sprint iPhone enthusiast yesterday was a day of good news, it was finally confirmed the third largest carrier in the U.S. would now carry the iPhone.

As promised, Apple shows off its latest iPhone Tuesday at “Let’s Talk iPhone Event”, and although the new handset was packed with new features and hardware like a new chip and improved camera, the general reaction was less than spectacular. Many had hoped to see the new rumored iPhone 5 released but this was not the case.

 On the carrier front, Sprint will become the third U.S. wireless provider to carry the iPhone, but it won’t come easy for the company. Like the other carriers, Sprint will have to buy the phones for around US$600 each, and then sell them at the suggested retail prices, starting at $199 with a two-year contract.

The Wall Street Journal reported that Sprint — the third-largest carrier in the U.S. and in a more difficult financial position relative to rivals AT&T and Verizon — made a commitment to purchase more than 30 million iPhones over the next four years. Neither Apple nor Sprint has confirmed that number.

The move has the potential to be a lifesaver for Sprint, especially as future iPhones with more advanced wireless capabilities come along. However, the initial capital could put a strain on current balance sheets.

John Feland, CEO of Argus Insights, said “It would make sense strategically for both companies. Sprint has the most mature and widespread true 4G network in the U.S. They are in desperate need of a winner. Apple needs a 4G network to push new experiences out to the iPhone faithful, especially in the face of competition heating up from Amazon.”

It’s a risky move for the company, but it’s the kind that can pay off well, especially when the company is in the position of going big or going home.