It will take 2 packs of Buildings, 1 pack of Streets, and 4 sets of Clips to make a decent 3x3 table out of Terraclips. I've done this and it is fun to play on, but is time consuming to assemble and hard to transport.
For ease of set of and more variety, I would first suggest building onto whatever Warmachine terrain you already have. trees, hills, buildings, wall sections, etc from Warmachine all work well. You just need MORE.
If you're set on Terraclips, this is what 2 Buildings and a Street set built me. I still change up from time to time and build a full board, but more often lately I just use the buildings standing alone rather than a fully assembled table.
http://www.wyrd-games.net/showthread.php?32425-My-new-Terraclips-board