Is that a mintage mistake?

I believe you probably meant to say, "Is this a mint error", in which case the answer is yes; it's a simple, common alignment error.

Occurs on a lot of coins, probably has no additional value whatsoever.

Coin dealers often ask for a slightly higher price for such, but I don't know how successful they are. If the rotation is close to 180º, then you can get a more substantial premium, but that won't be enough for a mortgage payment. Perhaps a nice lunch or dinner if it's a Lincoln cent or some other highly collectible coin. If it's a coin that few people know or care about, then perhaps a few extra dollars at best.

These are actually decently sought after by Italian collectors. However no where as far as americans.