Joe Taxpayer or John Taxpayer (Jane Taxpayer)

“Joe Taxpayer” or “John Taxpayer” (also “Jane Taxpayer”) is a generic name for a citizen who pays taxes. “John Taxpayer” is cited in print since 1920 and “Joe Taxpayer” is cited since 1934. Middle initials such as ‘Q” and “W” are sometimes used. “Jane Taxpayer” is cited in print from 1941; this form is usually used in the couple’s name, “Joe/John and Jane Taxpayer.”
 
Similar names for the average American include Joe Bag of Donuts, Joe Citizen/John Citizen/Jane Citizen, Joe Sixpack/Jane Sixpack, Joe Voter/John Voter/Jane Voter, John Q. Public/Jane Q. Public, Mr. and Mrs. America and Sally Soccer-mom.
   
 
   
Wikipedia: John Q. Public
John Q. Public (and several similar names; see the Variations section below) is a generic name in the United States to denote a hypothetical member of society deemed a “common man.” He is presumed to represent the randomly selected “man on the street.”
 
Variations
Similar terms include John Q. Citizen and John Q. Taxpayer, or Jane Q. Public, Jane Q. Citizen, and Jane Q. Taxpayer for a woman. The name John Doe is used in a similar manner. For multiple people, Tom, Dick and Harry is often used.

Roughly equivalent, but more pejorative, are the names Joe Six-pack, Joe Blow, and Joe Shmoe, the last of which implies a lower-class citizen (from the Yiddish schmo: simpleton, or possibly Hebrew sh’mo: (what’s)-his-name).
   
27 October 1920, Los Angeles (CA) Times, pg. II4:
John Taxpayer
by Eugene Brown
       
17 September 1924, Morning Oregonian (Portland, OR), pg. 10, col. 1:
And the cream of the jest is that the blue car was paid for by Mr. and Mrs. John Taxpayer.
 
13 November 1924, Dallas (TX) Morning News, pt. 2, pg. 14:
Chicago is willing to pay the expenses of 4,000 cadets on the trip. There will be a new city administration when old John Taxpayer learns this.
 
15 October 1925, New York (NY) Times, “To Deflate Bureaucracy,” pg. 22:
Some day John Taxpayer will howl so loud and so long that tho office-brokers at Washington will be scared out of their boots.
 
27 December 1929, Rhinelander (WI) Daily News, Letters, pg. 5, col. 5:
The average John W. Taxpayer is interested in knowing why Oneida assets are frozen in 1929 whereas they were readily liquidated in 1920.
   
22 March 1933, Hartford (CT) Courant,  “Bridgeport Government Under Fire,” pg. 1:
With the Democrats declaring for home rule and the Republicans for protection of “John Q. Taxpayer” from the political patronage holders, the politically opposing majorities of the two branches of the General Assembly tangled Tuesday on a bill for an issue of refunding…
 
16 March 1934, Covina (CA) Citizen,  “Wage Scale Takes Upward Climb” by Bill Dredge, pg. 2, col. 3:
With Joe Taxpayer leading the way in this elevation of the previously debased wage scale, we can sit on the sidelines and cheer when General (NRA) Johnson proceeds with the process of putting the wage scale screws on Mr. Corporation and his brother-builders.
 
29 August 1934, New York (NY) Times, “Painting Satirizing Roosevelt Hung in Westchester Institute,” pg. 3:
“Taking quite a trip to the east, we see a famous or infamous strip act with old John W. Taxpayer as the stripee.”
 
17 February 1935, Salt Lake Tribune (Salt Lake City, UT), pg. 8C, col. 2:
Here Are Pointers
For Joe Taxpayer
 
22 June 1941, Seattle (WA) Daily Times, “Taxpayers to get insight on defense costs” by United Press, pg. 2, col. 3:
DENVER, Saturday, June 21.—John and Jane Taxpayer will get a chance to rake the nation’s leading authorities over the coals Wednesday at a conference on government management.
   
3 April 1950, Portland (ME) Press Herald, “Washington And You” by U. S. Senator Margaret Chase Smith, pg. 9, col. 5:
“Jane Taxpayer” approved of it, but said she knew plenty about burdensome taxes.
 
22 November 1959, San Antonio (TX) Express and News,  ‘The Daily Investor” by William A. Doyle, pg. 11B, col. 4:
Yes, “Jane” or “John Taxpayer” can invest in those Treasury notes.
 
19 July 1967, Chicago (IL) Daily Herald, “DuPage County Seen…” by Jean Weston, pg. 12, col. 6:
But at the same time, Johnny and Jane Taxpayer should be sure of getting value from these meetings and as we’re now handling the matter…they just plain don’t.
 
27 October 1967, Salisbury (MD) Daily Times, pg. 4, col. 2:
This, the report says, represents a saving of more than $30,000 a month for the state and federal governments—meaning you, John and Jane Taxpayer.