I got this in a box-o-stuff recently and don't need it. And I have no idea what it's worth. So....$30 shipped? SOLD
Weird thing, though. It doesn't fit RT length rails (at least the rails I have with the two mounting holes). Also weird, I currently don't have a standard rail to see if it fits that. So you might need to modify the foregrip (or your rail) a little bit to make it work.
Still pretty cool, though. And in good shape. I haven't seen one for sale in ages.