I have two that I use regularly.
One is at a small LQS - the closest shop to my house. It's a punch card and after I fill it I get $25 off. It's not much, but I've turned in 4-5 punch cards over the years.
The other is at a Vac & Sew where I bought my Husky, and is right across the street from my favorite LQS - so needless to say, I don't have to make a special trip. He doesn't carry fabric, but he does carry thread and other notions. I have a thread card there and when I buy 10 spools (any size, brand, etc) I get the 11th spool free. I buy some of my thread from him, but not all.