I paid $675 for it, while retail is $799, so that's a decent discount. Local stores wanted retail and didn't stock it. And it's from a reliable source. Google showed prices as low as $640 but when I called the company advertising it they sounded fishy when I asked about stock and overnight delivery. They gave me no confidence, and for a 5% savings it wasn't worth it.
I picked up the 40-150 f3.5-4.5 on eBay for $95 shipped, that's a great deal for a lens that is so well-reviewed.