In AT&T’s end-of-the-year online refurbished phone sale, the wireless service provider is offering reconditioned iPhone 3Gs for just $99 — roughly half the cost of a new unit. It’s not the first time iPhones have dipped below $199. Just this weekend, the much-rumored Walmart iPhone debuted at $197 — just $2 lower than the standard entry price for the 8 GB iPhone 3G. Of course, the price of entry still comes with the two-year AT&T service contract with the mandatory $30/month data plan in addition to a voice plan.