The Amazon phone is coming. Finally. At least that's what the company is very likely to announce at a big press event this Wednesday. Amazon has long been rumored to be working on a smartphone follow up to its line of Kindle Fire tablets, and all signs are pointing that it will officially announce the device this week. Here's what we expect to see on Wednesday and why.

The phone

This one is pretty easy: Amazon published a teaser video for this event a few weeks back and you can see the top of a phone-like device about 42 seconds into it. Amazon's video features a lot of hyperbole and people impressed at what they are looking at, saying things like it "moved with me" and "that's pretty damn intuitive."

Chances are they are talking about a new glasses-free "3D" user interface, which has been expected to be included on Amazon's phone for some time. TechCrunch originally reported last year that Amazon was working on a phone with a "3D eye tracking interface", and it just reported that Amazon is using a special face-sensing technology to track the user's head movements. Apparently, users will be able to tilt their heads to the side to see hidden content or homescreens, an action that jibes with the behavior of the subjects in Amazon's teaser video.

3D user interfaces are not actually new — both HTC and LG tried them out in phones back in 2011, but those used special filters on top of the phones' displays to create the effect. It seems that Amazon is trying a different approach, utilizing the phone's motion sensors and some other unique hardware features.

The phone could feature a new shopping interface

There's been speculation that Amazon could be interested in a new shopping interface with the phone's 3D effects — and the New York Times today speculated that Amazon feels it needs something like a phone to bolster its shopping experience. The device could aim "to close any remaining gap between the impulse to buy and the completed act," notes the Times.

BGR followed up TechCrunch's report this spring with alleged pics and specs of the upcoming device, which show four cameras in each corner of the phone's front. Aside from these face tracking cameras, the phone isn't expected to have much else in terms of interesting specs. BGR reports that it will have a 4.7-inch, 720p display, a Qualcomm Snapdragon processor, and 2GB of RAM, which would put it in line with last year's Motorola Moto X, itself a mid-range device. Amazon could have upped the ante in terms of specs since BGR received its information, but we'll have to see what happens on Wednesday.

BGR

The price

The hardware for Amazon's upcoming phone sounds interesting, but the company could really shake things up with how it decided to price the upcoming device. Amazon has never been one to shy away from unique pricing schemes and it could debut something really different for its phone.

Amazon already uses advertising to offset the cost of its Kindle lineup, and it could do a similar thing with the phone. The company has also experimented with interest-free payment plans for its Kindle Fire tablets, which aren't unlike the payment plans utilized by T-Mobile, AT&T, Sprint, and Verizon for their no-contract smartphone plans. In a report on Tuesday, the Wall Street Journal claims that AT&T will be the exclusive carrier. Amazon's LTE-equipped Kindle Fire tablets are available for either Verizon or AT&T.

Amazon's never shied away from interesting pricing schemes

Another wild card is how Amazon might integrate its Prime service into the phone's pricing options. The company just launched a streaming music service that complements the free video services available to Prime members, and it could provide special deals for them on the price of the phone.

Either way, we don't expect Amazon to use sales of the phone to make a profit. The company has always priced its devices aggressively low, forgoing profits on the hardware itself in exchange for getting more people signed up for its services and buying things from its virtual shelves. There's no reason to expect the phone to be any different in this regard.

What's up with that invite?

One of the strangest things that's happened leading up to this event is the odd package received by attendees last week. Inside was a note from Amazon CEO Jeff Bezos accompanied by a copy of the children's book Mr. Pine's Purple House. Bezos' note says this was his favorite childhood book and that "the world is a better place when things are a little bit different."

It's hard to decipher the exact significance of the book and how it relates to what Amazon is planning to announce, but we'll be there in Seattle on Wednesday to find out.

Amazon could use this opportunity to announce updates to its Fire TV, Kindle tablets, and Kindle e-book readers in addition to announcing a smartphone. If Bezos' note is any indication, it's going to be "a little bit different" and surely interesting. Amazon's going to have to differentiate itself from the both the iPhone and the sea of Android phones already owning the smartphone market — integrating your smartphone habits with your shopping habits in a new convincing way could do just that.