Saw this on a VASSAL gaming board. It's free so I figure I'll give it a whirl and see how it stacks up to VASSAL and TTS.
http://battlegroundsgames.com/battlegrounds-gaming-engine/ (http://battlegroundsgames.com/battlegrounds-gaming-engine/)
I see that there is a demo. Is that what you meant by free? I'm also curious as to how this holds up to Vassal.
https://boardgamegeek.com/article/23206260#23206260 (https://boardgamegeek.com/article/23206260#23206260)
They were talking about it on facebook. It certainly seems to have some nice features that VASSAL could use but it doesn't offer support for pbem and it you want to host a game, one of the players will need to of purchased a license. Still, the more the merrier when it comes to these things I think.
I've been using it for a while. It's certainly useful though it has it's own little idiosyncrasies. It's not perfect but it's certainly easier to get something up and running compared to vassal.
I've mostly used it for miniatures gaming which it seems to work quite well for.