I think if you shop around and are willing to wait a little while you can find just as good a deal in store as online. I am always leery of buying big items like that online because returning them is such a bitch if there is anything wrong. Plus, I'll bet most of the big box stores will price match if you bring them a reputable online price (not a closeout/discontinued model/etc...)
So: if he's got to go get one now, buying online is the way to go. if not, I would shop around a little and watch for deals.
We were able to get our 42" Sharp Aquos LCD for $799 at the VA Canteen (neither my wife nor I are in any way service connected) and because it was in the VA, we didn't have to pay tax on it.
What size is he looking for and what's his budget (obviously because of the nature of the initial post I assume he wants to spend as little as possible, but where what is his upper limit?)