Amazon's Kindle digital reader is like a Wii for readers: Endless entertainment options, loveable hardware, extra features galore. Just today, Oprah showed how, with the addition of an digital memory card, the Kindle allows you to carry around FOUR THOUSAND books. An entire library, in your carry-on bag. Instant gratification when you want a new book or magazine. Plus blogs.

But two things have held me (and my credit card) back: price and price.

That is, the $359 price tag, and the cost to buy books and magazines to put on it. Even though Kindle books cost about $6 less than hard copies, if you get most of your books through the public libarary or second-hand sales like I do, keeping your Kindle stocked will end up costing you more.

In a moment, more on whether a Kindle could actually save you money. But right now, here's something that's convincing me to take the Kindle plunge: This morning, that booklover Oprah offered a $50 off coupon code, making the Kindle just $309.

The code is OPRAHWINFREY, and it's good through Nov. 1.

Now, to the question of whether owning a Kindle can save you money. Many have asserted it can -- in fact the Wall Street Journal argued that it can in two different columns. The best way, the Journal points out, to save money with the Kindle is not through buying books -- saving $6 a book, you'd have to buy 52 new books for it to pay for itself even with the Oprah discount.

The way a Kindle can really save you money, WSJ columnist Brett Arends says, is with its mobile data features. With Kindle's keyboard and basic Internet browser, some users may replace their cell phone's mobile data plan with the free Kindle service, saving $20 a month or more.

If you set aside your $20 a month for mobile data toward the $309 for the Kindle, you are only paying $5.75 a month for a year, then it's paid for. So if you buy one book a month, and cancel a $20 data plan, the savings WOULD pay for a Kindle in a year.

Then there are subscriptions. When I was a business reporter, I used to subscribe to the New York Times to read on the train. It currently costs about $6.70 a week to have the Times delivered to your doorstep. On Kindle, it's $13.99, a savings of more than $13 a month. So if all you did was read the NYT, it would take you two years for the device to pay for itself at the Oprah price. But other magazines, like the Wall Street Journal, currently offer better deals on the paper version than the Kindle version.

In conclusion, I'd say that SOME people would save money with a Kindle. Daily train commuters and people who spend a lot of time in airports could clearly save -- and would most benefit from the convenience of not having to go out and seek physical copies of their reading material. For me, a stay-at-home mom with no mobile data plan, there would be little to no savings.

But you know what? I kind of, really want one anyway. And my birthday is coming up. And, since I have a free trial of Amazon Prime, I could have one here tomorrow by paying just $3.99 to upgrade to overnight shipping. Oh, wait! I thought of something. I'm about to spend about $500 on a nice oak bookshelf for our dining room. To hold all those old-school books we buy at second-hand sales, etc. If I stop buying paper books, I won't have to buy any more expensive bookshelves. And there's always the savings to the environment if I convert my Chicago Tribune subscription to a digital one, even though they're the same price.

Commenters: Can you help me come up with any more justifications so my husband will read this and buy me a "money-saving" Kindle for my birthday?

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