Best Buy Now Selling iPhone 3G Refurbs Too
Best Buy outlets are now selling refurb 3Gs for $149 (for the 8GB model) and $249 (for the 16GB) -so both are $50 off the cost of a new model.
AT&T had also been promoting discounted iPhone 3G refurbs (and may still be - check this page for details) - at the same prices as Best Buy are currently offering.
As with new phones, the refurb models require a 2 year contract with AT&T - and come with a one-year warranty from Best Buy. These discounted units are available initially at 350 Best Buy outlets, and will be in all stores by the end of January.