The Northrop Grumman B-2 Spirit, better known as the Stealth Bomber, can launch conventional and nuclear weapons against the most heavily protected enemy lines on earth thanks to its ability to evade radar detection. Originally, it was supposed to be manufactured in a run of 132, but it was so expensive that the initial 1987 order was slashed to 21.
The cost of the B-2 program in 1997 was $737 million, or just over $1 billion today. Combined with procurement costs, the B-2 Spirit costs over $2 billion. The craft was first used during the Kosovo War in 1999, and it has been used successfully in Iraq and Afghanistan as well. They have also been used during the 2011 Libyan uprising, according to the BBC.