Quickly glancing at that....I might not be 100% accurate.
平成 = Heisei, A japanese era name.
Heisei (平成) is the current era in Japan. The Heisei era started on 8 January 1989, the day after the death of the Emperor Hirohito. His son, the 125th Emperor Akihito, acceded to the throne. In accordance with Japanese customs, Hirohito was posthumously renamed the 124th "Emperor Shōwa" on 31 January 1989.
https://en.wikipedia.org/wiki/Heisei_periodsooooo...
平成元年 = 1989 or Heisei first year.
平成2年 = 1990
平成3年 = 1991
I'm guessing that the below date
平成3年 10月 25日 - 12月 27日 = 1991 Oct 25 - December 27th
is some kind of competition window for all those hardware/accessories listed in some kind of "super gift campaign" スーパーギフトキャンペーン
賞品 = Award item
500名 = 500 names or 500 people etc.