From http://insideevs.com/cant-wait-afford-tesla-powerwall-build-300/:
The Tesla units comes in both a 7 kWh and 10 kWh version (details), priced from $3,000 to $3,500; which quite honestly for the sleek enclosure, and Tesla Energy packaging cache, seems like a pretty decent deal to us.
That being said, the product was/is not exactly coming to market quickly (it is just now shortly arriving to a select few lucky customers).
Place a new order, and well, you are probably looking at ~2017 as a reasonable delivery window.
Read More at http://insideevs.com/cant-wait-afford-tesla-powerwall-build-300/
Video at https://www.youtube.com/watch?v=Bk50IuWXg-c