So I zipped off to the nearest store that had one in stock and discovered that Walmart's online prices don't necessarily have anything at all to do with the prices on the shelves. $69!
But, as mentioned previously, I didn't want to be sans laptop for any length of time, so I bought it anyway.
In the course of doing so, I had asked a Walmart helper-tron-type person what the deal was with the prices (Me: "What's the deal with the prices?" Him: "Yeah, the prices online don't necessarily have anything to do with the prices on the shelves.") and found out that they have a thing called "site-to-store" or some such, where you buy an item online, and they ship it to the nearest store, for free, and you pick it up. And that way you get the online price.
So after checking the return policy carefully, when I got home, I ordered another charger through their website, this time for $49.
And thus it was that on my way home from work on Friday, having received my email notification of availability, I popped in to Walmart, made my way to the back of the store, and picked up a second charger for my laptop.
I then took it out to my car, removed it from the cardboard box in which it had been shipped, made sure I had the older, more expensive receipt, walked back into the store (via the other door), made sure to obtain a little sticker for my returned item, went to the customer service counter at the front of the store, and returned it.
(Her: "Reason for return?" Me: "I found the same thing cheaper online." Her: "Anything wrong with it?" Me: "Nope. It's not even opened.")
Which is all a very long and roundabout way of explaining that, in effect, on Friday, Wal-Mart corporation paid me $21.69 to carry a piece of merchandise from the back of the store to the front of the store.