The bartender says, "what'll you have?"
"It's been so long since I've had a good laugh", replies the redditor. "I'll give you $100 if you can tell me a joke I haven't heard before."
"That sounds easy enough", replies the bartender.
"I should warn you", the redditor says, "I browse /r/jokes so I've heard them all over and over and over again".
Curious, the bartender pulls out his phone and browses /r/jokes for a few minutes.
"How about this?" he asks, "A man is driving through a remote forested area at night when his car breaks down next to an old monastery..."
"Heard it.", interrupts the redditor. "It's reposted every month."
The bartender apologies and starts scrolling on his phone for a few more minutes.
"Ooh, here we go, so a blonde shows up at a rich guy's doorstep asking if she can do any chores for cash..."
"Heard it!!", the redditor snaps. "that's reposted every week!"
The bartender is flustered but tries again, furiously browsing the subreddit. "Aha! This one is sure to impress. What's the difference between Donald Trump's hair and a thong?"
"No, no, no!!!", the redditor cries out. "That joke is reposted every day!"
"OK, OK, please give me one more try", the bartender pleads. He scrolls furiously through his phone. "Nope... nope... nope... YES!! This is a great one!"
"OK, lay it on me", the redditor asks eagerly.
"Here it is", the bartender replies. "So a redditor walks into a bar..."
Edit: initially screwed up the Donald Trump joke. Embarrassing, since I see it every day.
Edit 2: gold! Now this redditor can actually afford to walk into a bar! They accept Reddit gold there, right?