And now, a break from the original series....
Pack #30: 1974 Yellow Poster Pack (Big Mouth ad)
During 2002, I started a thread on the Delphi Forum entitled "God doesn't want me to own a yellow poster pack." I had been trying to win one for a year, and I kept getting outbid. I finally did win one on ebay later that year, the one above. I subsequently obtained both of the other ad variations as well (the other two in the last 3 years). And while the average asking price for one on ebay at the moment is close to $600, I obtained all 3 for $125 or less, which is around what they're actually worth.