What's better than an Apple (AAPL: sentiment, chart, options) iPhone for $199? An iPhone for $99, of course. According to The Boy Genius Report, Apple may have plans to offer a 4GB model of its wildly popular iPhone for the low price of just $99 (with a 2-year agreement). The catch, according to Boy Genius, is that the phone will be sold at Wal-Mart Stores (WMT: sentiment, chart, options).

The move could certainly be a boon for AAPL, and a nightmare for Research In Motion Limited (RIMM: sentiment, chart, options) and Palm (PALM: sentiment, chart, options). The problem with such a deal would be that it could undercut sales of the 8GB and 16GB versions of the phone, as well as the iPod Touch - the 8GB Touch sells for $229 on Apple's website.

Apple traders are largely ignoring the rumor, however, as a Gartner report is dominating activity for smartphone makers this afternoon. According to the research firm, smartphone sales are continuing to slow, with third-quarter growth arriving up 11.5% from last year compared to growth of 15.7% in the second quarter. At last check, AAPL was off nearly 6% at $90.33 per share.