This isn’t a Wirefly or Amazon.com discount, the official Sprint website has reduced the Samsung Nexus S 4G to just $99.99 with a new 2 year agreement from Sprint. The Samsung Nexus S is the follow up to the original Nexus One and gets the official Android updates before any other device.
Typically 3rd party retailers are the ones to start deep discounting early, not the case with this device. Sprint has some impressive hardware coming out this year including the Motorola Photon 4G (July 31) and they are expecting a Samsung Galaxy S II variant as well. Also a leaked document a few weeks back showed that Sprint is expecting a follow up to the Samsung Epic 4G in the Samsung Epic 2.
Perhaps these new phones are the reason Sprint has discounted the device so much. Sprint is also in the midst of becoming fiercely competitive as the impending AT&T/TMobile merger looms.
Source: Sprint via Unwired