When my local has events, it's usually buy 2, get one free or buy 3 get one free for whatever cigar they're promoting. With each "unit" bought (meaning each 2 or 3 cigars, depending on event) you get a raffle ticket for a drawing at the end of the night.
The prizes usually run from an assortment of smokes to a box of smokes. One event - for General Cigar, had a humidor grab. 60 seconds in the walk in to grab as many GC cigars as you can hold and walk out with.
Food is always served, hot dishes and sandwiches, and his place is BYOB. Like Grapes said, it's usually up to the store for what they do, but this is what mine does.