Aoshima Grand Champion Best Volume 01
Price is per car.
Aoshima Grand Champion Best Volume 01 (Aoshima Granchan Best Volume 01) includes six car models with two colour variants (so, that's 12 in total) + apparently a "secret" car.
They are randomly packed into small boxes that resembled those small cereal boxes you took on holiday, then randomly packed into larger boxes of 12.
Since the boxes are sealed and identical, there's no way of me knowing which is which, so you may get duplicates. I have however been told that a full box "probably" contains one of each!