In a few days the SpaceX mission CRS-8 will launch from NASA's Cape Canaveral to the International Space Station. CRS-8 is a cargo resupply mission to ISS; its primary payload is the Bigelow Expandable Activity Module (BEAM), an inflatable expansion for ISS.
I've written before about how SpaceX (and recently, Blue Origin, but that's another post) represents a potential revolution in the cost of space launch compared to systems developed and operated by NASA. That's great, but it's also a truism that it's not enough to get to space - humans need a place stay (where they won't instantly die) once they're there. And that's where BEAM comes in.
The ISS cost $100 billion to construct, using NASA's technology. The total bill is estimated to be around $150 billion (including all costs from international partners), but about $50 billion of that was just the cost of launching the pieces on the Space Shuttle. So $100 billion was just for the strcuture, and that's a lot of money! According to Wikipedia, that's the most expensive structure ever made. It's a plausible claim anyway.
BEAM by comparison cost "only" $17.8 million. That's still expensive by most people's standards, but there are homes in London and New York that cost more. This is within the realm of something that normal humans can afford, and is certainly affordable to larger commercial entities.
Another useful comparison between Bigelow's structures and ISS is the internal volume, since that's where any potential people would live and work. ISS has an internal volume of 916 cubic meters. The Bigelow modules are numbered according to their volume, so the BA 330 has 330 cubic meters of internal volume and the (proposed) BA 2100 has (wait for it ...) 2100 cubic meters of internal volume.
In other words. just three BA 330 modules would have the same internal volume as ISS, and a single BA 2100 module would be more than twice the volume.
We don't have a purchase price to compare the BA modules with ISS because Bigelow is not offering them for sale. The business model to start is to lease the space to national space agencies and corporate interests for 60-days at a time or more. The pricing released in 2014 was $25 million for 2 people for 60 days, which works out to $208,333 per person per day. ISS by comparison works out to about $7.5 million per person per day, so we're talking about a 97% discount from the NASA price. And that's based on SpaceX's non-reusable rocket prices! Getting the stations in orbit is a big part of their final cost, so reducing that price by 90% will eventually lead to even lower prices for Bigelow's leasees.
The BA modules present the opportunity for any developed nation of reasonable size to have a space station as larger or larger than ISS for less than 3% of the cost. It also opens up the ability to go to places besides Low Earth Orbit. A BA 300 station could be landed on the Moon and essentially be a pop-up Moon base for six people. Or it could be placed in orbit around Mars. Or attached to an asteroid mining rig, much as deep-sea living quarters are a part of the modern oil & gas industry.
The big lesson is that when you reduce the cost of something by two orders of magnitude, a lot of previously quiet demand can make itself known. Bigelow has already signed agreements with seven national space agencies and an unlisted number of corporate interests. They're just waiting on a manned space vehicle to prove out so before launching them, and the Dragon v2 is expected to fly in 2017. Before this decade is out you should expect to see a lot more people in space.