Ron Guth: In 1982, the composition of the Cent was changed from bronze to copper-plated zinc; such pieces can be told apart easily by their weight. The older, bronze pieces are currently in demand because the value of the copper comes close to, or exceeds, the face value.
Building a set of Memorial Cents is easy and affordable IF the varieties are excluded. Most dates are readily available in Gem Mint State or Proof condition. Thus, this series makes an excellent starter set for new collectors.