Douglas Harper's Etymology Dictionary
Wiktionary
n. 1 (context US English) A copper penny. 2 (context US colloquial English) A very small amount of money.
WordNet
n. something of little value; "his promise is not worth a damn"; "not worth one red cent"; "not worth shucks" [syn: damn, darn, hoot, shit, shucks, tinker's damn, tinker's dam]
Usage examples of "red cent".
Gone to make do and mend, thinks I - and since H didn't have a red cent to requite her, it struck me as a capital time to resume my scattered togs and make tracks for the ministry.
His son, who drops in with black shepherd in March 1949, doesn't get to see a red cent at first.
Now tell me where the money is, and every red cent better be there.
I wanted the ten dollars a week the job paid, and I got it, and you better believe me when I say I earned every red cent of it.