JWST Nature summary
Nature has an interesting article on JWST and its cost and impact -
Despite this, the cost has continued to climb, alarmingly jumping almost $1 billion in 2005 alone (see graph). NASA's requirement that the programme beef up its contingency fund added a little over $200 million. A delay in the government's decision to move from a US launcher to the Ariane added an estimated $300 million as highly paid engineers were unable to move forward until they knew which rocket they were designing for. The situation is particularly embarrassing given that the cost of delaying the decision ended up being greater than the cost of the launch. That delay, and a NASA decision to rearrange the project's long-term budget yet again, saw the launch slip from 2011 to its current date of 2013. Every slip increases the total cost.
Rehashes a lot of known stuff, with interesting "astronomer quotes" interspersed, but it summarises a lot of the issues well.
Worth a read.