That's a really general question, almost too general too be answered. My first two questions would be 1) What kind of promotions are you trying to do (for instance BOGO, 1/2 off, etc) and 2) When I think promtions, I am not sure scalability is a factor... most systems are designed to have individual promotions configured indepently, but what you can do will ultimately be determined by the system you are using. What POS system are you working with?