"B.O.G.O." is an acronym for the term "Buy One, Get One (Free)".
The description on this item is a reference to picking up double bombs in the original The Binding of Isaac where the message "1+1 Free!" would pop up in the bottom right whenever picking up a double bomb.
Bombs become 
Double Bombs.
Humbleing Bundle: No effect.
The Binding of Isaac: Rebirth
