If you live in the US and want to buy a new Kindle Fire that won't show advertisements on the lock and home screens, you're out of luck. Unlike Kindle e-readers, which come in ad-supported and non-ad-supported models, there is no option for US customers to purchase Kindle Fires without "special offers" that display on the lock screen and the lower left corner of the home screen.

The ads are US-only, for some reason. "Kindle with Special Offers & Sponsored Screensavers is only available in the US," a note on the Kindle Fire product page states. Fire tablets are also available in France, Germany, Italy, Spain, and the UK. (UPDATE: It turns out the ads aren't US-only, despite that Amazon statement. They're also on the UK, German, Spanish, and Italian versions.)

Amazon promised to give owners of ad-supported Fires a $5 credit to its MP3 store and a $5 credit toward "select titles" in its instant video store. Other screensaver advertisements will come from brands such as AT&T, Discover, and Intel with offers like "a $10 Amazon.com Gift Card when a customer uses their Discover card to purchase a digital product on Amazon."

Amazon has been selling Kindle e-readers with ads both on the lock screen and the bottom of the home screen for a couple of years. But the ad-support model for the latest Kindle Fire marks a shift in its strategy. The first Kindle Fire featured lock screens that Ars reviewer Casey Johnston found "stunning," with photos of retro objects like type sets, colored pencils, typewriter keys, and rolled up magazines. Kindle e-readers, meanwhile, allowed users to pay extra for devices that did not include the ads, and instead showed black-and-white images of famous authors. Even if you bought a Kindle with ads, you could pay the price difference to turn them off later.

We've asked Amazon why the ads are US-only, and whether customers can pay to turn them off. If there is such an option, it doesn't seem to be mentioned in the Kindle Fire announcements or the Amazon sales pages. The prices are quite good, though, beating or matching the prices of tablets of comparable sizes. A 7-inch Fire costs just $159 for the version without a high-definition screen, and the 7-inch HD version starts at $199 for a 16GB version. A 32GB version costs $249 (the same price Google charges for a 16GB Nexus 7). There is also a set of 8.9-inch Fire tablets ranging from $299 to $599, with anywhere from 16GB to 64GB of storage and the option to have 4G LTE connectivity in addition to standard WiFi.

When Amazon unveiled last year's generation of Kindle e-readers, it cost $40 extra to buy a Kindle Touch without ads. The e-readers unveiled yesterday also have different prices for the versions with and without special offers, but that difference has shrunk. A Kindle Paperwhite 3G, for example, costs $179 with special offers or $199 without. That $20 price difference holds true for all the new Kindle e-readers.

If you took the earlier $40 price difference to mean that each Kindle with ads was worth another $40 to Amazon in increased sales, then the change may suggest the ads didn't bring in as much revenue as Amazon expected. But the Fire has a greater ability to lure customers into buying Amazon products, whether it be digital music or video, or physical goods purchased through the tablet's Amazon store app. If the special offers both lower the price of the hardware, bringing in more buyers, and lead to additional sales from Amazon's various shops, it's easy to see why Amazon wouldn't want customers to turn the ads off.

UPDATE: Engadget reported (incorrectly, as we now know) that there will be an option to turn off ads. The confirmation came not from any public statement made by Amazon, but from a customer support representative's e-mailed response to an Amazon customer's question. "I understand that you would like to opt out of the special offer and willing to pay extra for opting out special offer. Options for unsubscribing special offer will be announced soon," the Amazon customer service rep told that customer, according to Engadget. That doesn't sound very official to us, so we'll wait to see if any more definitive word comes from Amazon.

UPDATE 2: Unfortunately, it turns out our suspicions about the reliability of the Amazon customer service rep were not without good reason. According to CNET, Amazon confirmed to the publication "that there will be no way to buy out of the Special Offers ads." Amazon has now also confirmed to Ars that no option to opt out of special offers will be available.

It's possible Amazon could change its mind and issue a software update allowing such an upgrade, but for now it is explicitly saying that it will not. (And yes, Amazon has now, one day later, changed its mind.)