Welcome to the forum! What you have there is a Gerber MPT, the Military Provisional Tool. http://wiki.multitool.org/tiki-index.php?page=MPT The original sheath too! For $15, I'd say you did pretty good. What sort of shape is it in? Gerber is known mostly for their sliding-head plier designs, but the MPT is a pretty neat piece.
I'm pretty sure even Chako doesn't have one of these. Welcome to MTO!
I have two.