In store only. Online price is $4.50 per block.
Woolworths stock 3 types of Cadbury cooking chocolate blocks in their stores. Dark, milk and white.
Anyway in all my local Woolworths stores the 200gram blocks of Cadbury cooking chocolate (all varieties) are $1.80, reduced from $3.
The signs say "Clearance". It's possible they aren't going to sell the 200 gram blocks of Cadbury cooking chocolate anymore, or it might be they are simply switching to a new size/packaging.
Pretty sure this is a nation wide deal. Others might want to confirm in the comments.
Anyway all you cooks out there stock up!