Unlike NVIDIA's G-Sync, no specialized hardware is required to support FreeSync. This week at Computex, AMD was showing off the first FreeSync capable monitor
Standalone monitors as is typically do not support this technology meaning you DO need specialized hardware. You just don't need that expensive GSync chip. I hope Nvidia responds to this by supporting freesync as well.
But judging by the differences that GSync is a much more complicated implementation of this, I am sure there are benefits it has that freesync does not (not that I care, I prefer freesync because it's hardly any extra price for me to get that)