Here are salaries at glassdoor. Nothing amazing here: http://www.glassdoor.com/Salary/Amazon-com-Software-Engineer...
The deer in headlights wide-eyed look on my recruiter's face (after I had finished all the interviews) when I told him what I currently made in a smaller metro and what I was looking for is something that will be seared into my memory forever.
I can't remember if the word "salary cap" was used or not, but it was definitely implied.
I offered to accept a lower base with alternative compensation options (even vacation days), but it was already too rich for their blood.
I think they gave it some serious thought, but I got a call a week later that they simply couldn't do it.
Your signing bonus is pro-rated and you pay it back if you quit before one year, and your moving expenses are also paid back over two years if you quit before then. Your stock grants vest heavily in the back-end over four years. Every year you get a review and new grants are included in your total compensation package as your "salary". It's a sort of lock-in system that helps keep you invested in the company as you keep earning stock etc, but that was my perspective. Nothing exorbitant, and that fits with the Amazon ethos of "frugal".
To be honest, I think it was a miss-match in positional terminology. I was going for a PM role, which in my current career path is basically the CEO of a specific project or program for part of a company. (These programs can be very big, the largest program I ever worked on as part of the PM staff was north of $130m/yr. but for a wide variety of reasons I prefer the smaller $5-20m work, much more fun to run). Typical compensation is a base salary + specific performance bonuses + contract win bonuses (+ large option grants as bonuses in the kinds of companies that do that sort of thing).
I got the sense that at Amazon PM roles are much lower down the totem pole positionally and act more like coordinators in the organization and don't have as much agency as I was assuming. I was honestly just looking for a change of pace and probably would have accepted whatever they offered even if it was quite a bit lower than what I considered my market rate, but I fouled it up early on and didn't recover well.
I also felt that future compensation was more anchored to your starting compensation than at other companies.
Furthermore, they don't increase your salary over time, so after a while, that OK starting salary drops below the average.