On January 10, 1962 NASA began developing the Saturn V rocket (still the most powerful rocket to have ever flown). Just five years later, on November 9, 1967, it flew its maiden flight. The total cost to develop and build the first rocket (Apollo 4) was 185 million dollars (adjusted about 2 billion dollars today).
In November of 2005, NASA began developing the Ares rockets (later on becoming the Space Launch System). Having spent over 18 billion dollars on the program it's still not expected to fly until summer of 2020.
Let's recap -
- Apollo V: 5 years - 2 billion dollars spent
- SLS: 15 years - over 18 billion dollars spent
Oh yeah, one thing I forgot to mention, after the SLS flies it's first mission the Saturn V will STILL be the most powerful rocket to have ever flown. How in our modern technological age is this possible?