A play on the term from the prohibition years, it's a bar (usually privately owned) that you can smoke cigarettes inside of even though it's against state law.
Smoker's Deal is a term used when you get an unbelievable bargain for something. Smoker's Deal is something that a crack head would offer you on a product/service at a super low rate.
"Hey man I'll sell you this 52' inch flat screen for 20 bucks!".... "Damn that's a smoker's deal right there!"