Amazon just did WHAT??? Get refunded and keep the book?

WOW... I'm blown away right now, seriously. I only buy books at Amazon* (I know, I should be supporting local bookstores, etc... but I love books and I need to buy affordable books) and I always use their free saver shipping (though I've recently decided to dump netflix and get an Amazon Prime account so I can get free shipping always and be able to watch streaming video).

If you're not familiar with it, the free shipping requires that you buy 25 dollars in books, so I always need to buy "tag along" books with any purchases. This time, I was buying one of my favorite cookbooks of all time, Deborah Madison's Vegetarian Cooking for Everyone as a wedding shower gift to a friend, and I needed to spend about 5 more dollars (a very hard thing to do), so I bought Rick Riordan's Kane Chronicles Survival Guide for my son as a surprise, since he'd been asking for it for a while. Well... when we received it, it was a great disappointment to him because he had already bought the electronic book and I didn't know about it! :(

Today I went to Amazon to get the refund process started and... guess what? They told me they're giving me a refund and I can keep the book!! What???!!... these guys are making such big profits that they can afford to give me a book for free? Seriously?! I don't know if I should be happy or appalled, but the thrift-addict in me is cheering and jumping up and down! (and, best of all, my dear "thrifty person in training" son will be very relieved that we just saved 10 dollars -- he'll probably want to claim it to spend it in Legos!). What do you think of that?

In any case, I'm waiting for the refund now, I'll let you know if it really happens, but I think it will and now I'm really curious to know if this has ever happened to you before.

* And in two discount places/"warehouses" in our area. I hope that is OK, since I can't afford to support small independent book sellers.