T-Mobile Sold 500,000 iPhones, Could Top Sprint

announced this morning that it has sold

since the product arrived at the carrier less than one month ago.

began selling the T-Mobile iPhone on Friday, April 12. Sales were so high that it created one of the

in the carrier's history, and reportedly left T-Mobile scrambling to replenish its supply of Apple smartphones. By selling 500,000 units in less than one month, T-Mobile could eclipse the 1.5 million units that

averages each quarter. This would be an impressive feat considering the fact that T-Mobile is significantly smaller than Sprint and is the only carrier to offer unlimited data without throttling. T-Mobile, however, is the only carrier that happily promotes the iPhone at full price. The iPhone 5, for example, starts at $649. This fee allows customers to purchase the device without a contract. It also enables them to avoid the high subsidies that come with other monthly packages from Sprint,

and

. While T-Mobile is proud of its offering (which leads to a higher up front cost but a lower monthly bill -- and potentially a better deal over time), Apple's marketing scheme has led to

from bloggers who argue that the iPhone maker is being unfair. In a piece titled, "Does Apple Store Discourage T-Mobile iPhone Sales?",

criticized Apple's in-store rate plan listings because it displayed the prices ($649 for the T-Mobile iPhone 5, $199 from other three carriers) without an immediate explanation as to why the prices vary so greatly. Some shoppers may be unaware of the savings that T-Mobile can ultimately provide. That has not seemed to hurt T-Mobile iPhone sales, however. Part of attraction could be due to the monthly fee. While AT&T, Sprint and Verizon start at roughly $80 per month, T-Mobile plans start at $50 per month. At that price, users will only receive 500 megabytes of high-speed data, but for an extra $10 they can receive 2.5 gigabytes. For $70 per month -- the most expansive plan available -- users supposedly get "unlimited" 4G data. By comparison, Verizon's $80 plan offers a mere 300MB of data. From that perspective, the $649 price tag may be very easy for consumers to swallow, especially since T-Mobile will allow customers to pay for it over a two-year period.