“A guy walks into a bar…” is a typical form of what has been called the “bar joke.” One version is:
 
“A file folder walks into a bar, orders a drink and says, ‘Bartender, put it on my tab!’”
 
The joke has been cited in print since at least 2007. “A duck walks into a bar and says, ‘Put it on my bill!’” is a similarly themed joke.
     
 
ClutchFans
CHEETOS
macalu
09-10-2007, 01:27 PM
a manilla folder walks into a bar, orders a bunch of drinks, and tells the bartender, “put it on my tab.”
     
Walks Into a Bar Jokes 
TUESDAY, MARCH 17, 2009
(...)
A file folder walks into a bar, orders a drink and and say “Bartender, put it on my tab !”
 
Twitter 
Billy Idle
‏@funinmyhair
so a manilla folder walks into a bar and says put it on my tab
4:45 PM - 20 Sep 2009
 
Twitter
Brand Gamblin
‏@brandg
Duck walks into a bar, orders a gin and tonic, and says, “Put it on my tab.” . . . no, wait. DAMMIT!
2:53 PM - 23 Jul 2014
 
Twitter
S.P.Richards Company
‏@SPRichards
A hanging folder walks into a bar. “The usual?”, asks the bartender. “Yeah”, says the folder. “Put it on my tab.”
2:46 PM - 27 Mar 2015