Despite being #9 in unit sales for AT&T, the iPhone is the company's #1 revenue generator online, according to a report published by comScore Wednesday. The firm said that flagship phone offerings from Apple (iPhone), HTC (G1), and RIM (BlackBerry Storm) were generating substantially more revenue for their carriers, despite their much lower unit sales ranking.

Sprint's Instinct by Samsung was the one exception to this finding, as it was the #7 revenue generator for Sprint, and #15 in unit sales.

The firm's study measured shopping and purchasing behavior at the four major U.S. carriers in terms of handset sales and mobile data plans. While much of the coverage on the Apple's iPhone tends to be focused on the smartphone subset of the market, comScore's report measured this data across the spectrum of the carrier's product offerings, including all of the free (via subsidy) phones, refurbished phones, etc.

The results of the report are that it's the higher-end customers that are bringing in the most money for the carriers. While not specifically addressed in the report, one of the contributing factors would be the fact that the iPhone, Storm, and G1 all need data plans to take advantage of their smartphoness, and the carriers are able to charge a premium for those data plans in part because of the exclusive deals to carry their respective phones.

High End Pays for Carriers

The report also noted that an overwhelming percentage of all four carriers' top selling phones were given away for free (with contracts), meaning that the company's aren't seeing much, if any, revenue from the lowest end of the market.

To add further context for how Apple and its smart phone competitors fit into the cell phone market, we should look at the percentage of phones that are free to users (with contracts):

Apple's iPhone is also subsidized by AT&T -- most estimates place that figure at approximately $400 per iPhone -- but consumers do pay for part of the device directly. Apple's 8GB iPhone is priced at $199 with a two year contract, while the 16GB unit is priced at $299.