http://www.aliexpress.com/wholesale?...tId=0&manual=y
Well, looks like you can buy a 9.7" screen for less than $150, although even the knock-off products cost at least $200. 9.7" is quite a bit smaller than true A4 though, so it would cost even more. I don't even think they make LCD tablets that are A4.
In comparison, the screens alone for 6" readers seem to be retailing for about $30ish at the lowest. (
http://www.aliexpress.com/wholesale?...tId=0&manual=y). Of course, Amazon is probably paying way less for them. I found an iSuppli teardown claiming that in 2011 Amazon was paying that much for the screens. (
http://www.mainstreet.com/article/sm...-costs-84-make)
Interestingly I see on that site that the cheapest 6" e-ink reader (as opposed to just the screen) is $65, which means that Amazon is not selling theirs for much more.