Surprise! When you buy 3 packs, you get 1 free (or when you buy 4, you get 2 free). The free packs are automatically added to your cart, so you don’t have to. That means that you won’t know what the free packs are until you receive your order (which makes them a fun surprise!), but surprise packs are also totally on us and you aren’t charged for them.
Since surprise packs are determined by fate (meaning randomly picked by our system), you won’t be able to select the color of them. But you wouldn’t want to ruin the surprise anyway, now would you?