Musk has used the pallet of cash analogy several times.

Here is Musk using it in regards to saving the fairing @ ISS Research and Development Conference 2017:

https://www.youtube.com/watch?v=5cPMS6cT0Ig&t=825

In regards to the first stage (booster stage) at Code Conference 2016:

https://www.youtube.com/watch?v=wsixsRI-Sz4&t=545