I´m Henrik, first post here and sort of beginner at this ( use to do some embedded stuff some 15 years ago and picked it up again recently )
I just did a shopping list for this project, Version 2.0 if I got it correct
here it is: http://my.aliexpress.com/wishlist/shared.htm?groupId=3106453469
As an example it should be about 20 euros if you buy to be able to make 5 whole sets.
I added 3 additional and optional things to the original BOM:
battery holder + battery connector to make it easier to change them ( I think )
I did this for people searching for the components needed that does not have any or very few before starting the project.
Only thing extra needed I think would be some additional cable and a arduino UNO or some other way to program the single chips. But I assume you already have a UNO if you read this
And a soldering iron and that stuff.
(if even one person found this useful I guess it fulfilled its purpose)