Ron Guth:
Among all the Shield Nickels, the 1880 has the lowest mintage of any circulation strike date in the series. The problem with this situation is that the low mintage consists primarily of Prooflike examples. Thus, a poorly made proof example, of which there are many, is often presented as a circulation strike, which is worth considerably more than a Proof. To counter this, we recommend dealing only in certified examples, because these have been checked out and vetted by the experts at PCGS.
The extremely low population of certified Mint State examples consists of less than two dozen that have been certified by PCGS. Of those, only a single MS66 exists, with none finer.