The 1/2 price cigs can be purchased within a 5 10 minute walk in just about any direction from SkyTower in Wroclaw although I'm sure every city is different.
Yes, In Warsaw there's only one place near the centre where it's overt. Apart from that, you have to know that the little old lady with the stall or whatever has them.
In rural and suburban areas almost every kiosk
Again, not round Warsaw - the police etc are very keen on this.
With alcohol/cigs in large quantities, it tends to come through Poland rather than originate there. It looks like this is what happened with the lorry driver in the original post.