$1B divided by 700 is about $1.4M each. Is that just the build...

$1B divided by 700 is about $1.4M each. Is that just the build cost or including the launch? The articles I've read say it will be an initial 800 satellite constellation too. I will try to clarify that.
Regardless I imagine they are factoring in a large amount of economy of scale and are assuming the cost will reduce quickly over the next few years in order to come up with that figure. Their test microsats are reportedly 400Kg each. So assuming their constellation satellites will weigh similar and assuming SpaceX can launch for $10,000 per Kg that is $4M per satellite (thats $3.2B for 800) just for the launches, not even factoring in the build and design costs.
SpaceX is playing this one close to the chest and detailed information is hard to find.