That rep is clueless. There's a link right on the MBA page where they want you to tell them about a lower price. And, Amazon often does price match computers.
http://www.amazon.com/Apple-MacBook...ZP4/ref=sr_ob_1?ie=UTF8&qid=1311272456&sr=8-1
scroll down to the bottom of that page
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That's incorrect as well. Amazon does not price match unless it's TVs. Yes, they have a link for you to tell them a lower price, but that isn't regarding price matching for previously made orders. They want to be competitive for future orders. They want to know about someone else's lower price, so they can lower their prices for those who will be buying in the future. It's not for you to use after you already bought the item.
Taken directly from Amazon's pricing information page....
Amazon.com said:With the exception of TVs, Amazon.com doesn't price-match with other retailers (including those who sell their items on our website). We do, however, consistently work toward maintaining competitive prices on everything we carry.
http://www.amazon.com/gp/help/customer/display.html/ref=hp_468502_guarantee?nodeId=468502#guarantee
Obviously, there will be some reps who will price-match for you, but that is not the policy. More the exception than the rule.