With regards to FreeSync, I'm sure I read somewhere (might have been this forum, so who knows how accurate it was) that people don't have to implement VESA standards and in a lot of cases they actually have to pay to be allowed to support them. If this is on a feature-by-feature level then companies may have to pay/license the V-BLANK DP-1.3 stuff. This may actually cost them and in that case I'd imagine they'd pass the cost on to us. Now since it's unlikely they'll do 2 versions of the monitors it could be hard to tell if they are more expensive or not because of this feature. Just be cause we can't tell doesn't mean they won't be. I'd guess it won't cost as much as the extra Nvidia hardware though, Cheaper-Than-Nvidia-Solution-Sync is probably less catchy than Free-Sync.
Personally until someone can show me 2 version of a monitor, one with FreeSync and one without, I won't be convinced that there is no additional cost at all for having the new technology. Even then I'd question if they've just raised the price of the monitor without to make it seem like that. So what we'll need is an existing monitor on the market to then be released with no changes other than the new tech so that we can tell if it's actually free.