We can easily assume Alarielle will have the same price as the Maw Krusha.
Now I'll speak in Euros as it's easier for me
With some friends we spoke about that and we came to a 240 euros release, overall.
Alarielle 90
Drycha 65
40 and 45 each the other boxes, or something like this
But it's only a guess
as for the release, I would say they'll go in pre-order this week, because they should also release some orruks.
Therefore: Sylvaneth July the 2nd, Orruks July the 9th, General's Handbook July the 16th. Does it makes sense?