Cost of LCD displays

I’m designing a product with an LCD display; what is the production cost of these?

Is it for example considerably more expensive to produce the iPod with color display as opposed to the monochrome one?
To stick to apple: What is the main motivation for the display-less iPod shuffle? Is it losing the display to reduce the price, or lose the display to get rid of buttons?
How big effect does the resolution have on the price?

Displays and batteries are extremely expensive compared to other components. The shuffle ditched the display to keep it cheap, but also to differentiate from the iPod Mini.

After all, there are competitors in that size/price-point with displays (but without batteries:)