Something like warzone 2100 or Minecraft
Something with creative abilities to like make units or like add your own sprites to and play with other people…
And when I say strategy I mean like buildings resources and money…
Please let it be a free link rather than a demo
How about Goodgame Empire?
http://toomkygames.com/games/online/goodgame-empire?
hope this would be helpful.
If you want shooting then battlefield is for you
If not you can play the 7 days to die its like minecraft but with better quality and has zombies and you can build and do the stuff you mentioned above hope this helps