http://www.deltaforce.com/catalog/pg16.html#3864
Only $2 a shot!

Clearly they are misrepresentating the ammo as armour-piercing, which if it was really, would probably put it in the $2 range.  But SS109 is not AP, it does has a steel penetrator but most people don't know the difference.  And they pay and they shoot the ammo and it goes thru certain steel in SOME case where maybe M193 and others won't and they feel happy that it will perform on armour.

Edit:  I know this post was in humor, too.