You're potentially going to save tremendously buying online, but Heather is right that seeing/touching in person is practically a must for these products. Online, practicaly everything remotely "silver" in color looks the same, where in person you'll see a wide variance in material finish and quality.
That said,
faucets.com http://faucet.com is one place a friend recently saved some dollars buying a Delta touch kitchen faucet. Very nice product. That said, the week after she bought it I found a better price elsewhere online.
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So first narrow your choices to a few products and then comparison shop like everything else. Don't overlook eBay.
The big box stores are only going to have basic builder-level products by the way. But you might find something you like there anyway.