What is the value of a hollowed-out tails-side-only penny?

Answer 1

What you have is part of a novelty coin, or part of a coin used for illusions. You may be able to find a buyer for it on eBay, but it has no inherent collector's value, nor is it spendable, technically, as a cent. (The hollowing-out, by the way, was done after the coin was minted.) Somebody hollowed out a normal penny and either ground off the edges of a dime, or ground off the back and the edges of another penny, and then glued this piece into the hollowed out area of the first coin. This was done to make either a two-headed coin, or a coin that would appear to change from a penny to a dime in a magic trick. These coins are mass-produced and sell for a couple dollars on eBay.