First, the iPhone: AT&T is selling therefurbished 8GB iPhone 3Gs for $49.99 with a two-year contract. Gizmodo said it well: "That's cheaper than a lot of dumbphones." Check out AT&T for more details.
As for the Palm Pre: You can get it for only $99.99 at Amazon with a new two-year service plan. The phone itself has a list price of $499.99, so you're getting quite a deal by starting a new plan with Sprint. Unlike the iPhone listed above, the Palm Pre being sold here is new, not refurbished. Visit Amazon for the full scoop.