I always try to keep an eye on the sale page at GunMag Warehouse. They always have a few really hot deals and their low cost shipping makes them impulse buyable.
They just put their Magpul MOE Vertical Grips on sale for $9.99. These grips are made to direct connect to the older style MOE Hand Guards but I have modified them for use on KeyMod, M-LOK, and many other free float rails simply by grinding out the plastic tabs as necessary. You can even chop them off to whatever length you desire (like a handstop) and stipple them. They are like a blank canvas!