As much as Id like to see Franklin's discussion on colonial scrip be true; I have never been able to verify it.
I have never read it in the copy of the autobiography I have.
It may be in a later copy made in the 1800s, but Ive never been able to see a copy to check.
About the only thing I could find that remotely came close was declarations of the stamp act congress, #9 specifically:
9. That the duties imposed by several late acts of parliament, from the peculiar circumstances of these colonies, will be extremely burdensome and grievous; and from the scarcity of specie, the payment of them absolutely impracticable
Which I assume is in reference to the currency act of 1764.