Green’s Dictionary of Slang

1. (orig. US) the practice (ostensibly illegal and generally denied by its practitioners) of bribing (with cash or kind) those with access to the public to tout a product.

1938		Variety 19 Oct. 41: The payola element had made their deals with bandleaders on the expectation that they continue to get 19c, thereby making it profitable to do business with the plug at a rate of around 10c a point [OED].
1940		L. Pound ‘Guide to Variety’ AS XV:2 205/1: payola. Bribery, the unethical practice of exploitation.
1953		Time 23 Feb. 56/3: A world where cut-ins (giving a performer a share of a song’s profits), hot stoves (open bribes) and other forms of payola were standing operating procedure .
1961		H. Ellison Rockabilly (1963) 143: This was going to hit every lousy penny-ante fan-mag in the country unless the payola was spread thick as peanut butter.
1973		Newsweek 30 July 62: Witnesses who will be granted immunity for telling what they know about payola and drugola.
1989		J. Morton Lowspeak.
1990		R.G. Barratt ‘Kill Two Birds’ in What Do You Reckon (1997) [ebook] The old payola. You know — eat at so-and-so’s restaurant [...] drink brand X bourbon.
1999		Guardian Guide 19–25 June 4: There was a strong whiff of payola in Clark’s playlist.
2008		J. Niven Kill Your Friends (2009) 71: The good old days of the fifties — the golden era of payola.

2. attrib. use of sense 1.

1938		Variety 19 Oct. 41: The payola element had made their deals with bandleaders on the expectation that they continue to get 19c, thereby making it profitable to do business with the plug at a rate of around 10c a point [OED].
1969		N. Cohn Awopbop. (1970) 53: Most of the shenanigans took place in Philadelphia [...] until its status was destroyed by the payola scandal.