What is the value of a 1975 aluminum Lincoln penny?

There are no references to such a coin anywhere. There were a number of test cents struck in aluminum in 1974 but none have surfaced on the market or in private hands. I can think of at least three possibilities: 1. The coin was plated by someone after it entered circulation. This is most likely. Compare its weight to another cent from the same time period. If it weighs about the same then it's almost certainly plated, since aluminum is much lighter than copper. 2. The coin is an off-metal strike. This happens when a planchet (blank) for a different coin (a foreign coin, another denomination, etc.) is accidentally mixed in with the intended planchets. You'd have to take the coin to a dealer or other expert for evaluation. 3. It's a privately-made copy. Unlikely, but not impossible. Again, it would have to be examined in person.