Have you tried couponcabin.com, flamingoworld.com, retailmenot.com, even Google? Have you registered with any rebate sites like Ebates.com or Bing? Not saying any of this will be successful, but they're often better than shot-in-the-dark requests for codes
That's okay - this is always MY first thought, too! Then I stop and think, "Wait. What are the odds of anybody on the DIS even knowing what Shnoop (for example) IS, never mind having a code for it? And (thwack!) Ebates isn't going to get me any money if I don't USE it!!!"