Mad magazine offers satire on all aspects of life and popular culture, politics, entertainment, and public figures. They are really good at making mock ads and here are some examples of some of their funnier ones. these are from the 60's and as such pull no punches and go for the jugular.
A Breck shampoo ad parody from 1964 featuring, yes, a Ringo Starr illustration.
As someone who remembers the real print ads, I love this one.
As the son of Appalachian Trail hillbillies, I can confirm that this Maytag spoof is correct.
Mad also often hit the cigarette industry as a whole with their fake ads.
Political correctness? What's that?
Parody of the famous Tareyton ads.
Miss Clairol — and women who dyed their hair blonde — get hit hard.
Brigitte Bardot for American Ex...pense.