as phony as a three-dollar bill

(as) phony as a three-dollar bill

Completely and obviously false, fake, or illegitimate; not genuine or authentic in the slightest. (There has never been a three-dollar bill in circulation in the United States.) Primarily heard in US. The course claims to teach you how to get rich in a hurry, but I can tell it's as phony as a three-dollar bill. The senator's hammed-up, teary-eyed speech was phony as a three-dollar bill, if you ask me. The guy said he was selling Rolexes, but this thing is as phony as a three-dollar bill.
See also: bill, phony
Farlex Dictionary of Idioms.

(as) phony as a three-dollar bill

and (as) queer as a three-dollar bill
mod. phony; bogus. The whole deal stinks. It’s as queer as a three-dollar bill. Stay away from him. He’s phony as a three-dollar bill.
See also: bill, phony
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • (as) phony as a three-dollar bill
  • phony
  • phony as a three-dollar bill
  • (as) queer as a three-dollar bill
  • as queer as a three-dollar bill
  • dill
  • ninebob
  • phonier than a three-dollar bill
  • queerer than a three-dollar bill
  • (as) bent as a nine-bob note