The man walks over, a little confused by the sign. “Did you make a mistake with the sign? It should be the other way around, or it’s not a very good sale.”
The merchant smiles in response and says “Nope, you saw correct. £1 each, or 3 for £5. It’s been getting me a lot of customers, so it must be doing something right.”
“But it’s completely backwards! …Let me try to explain another way. I’d like to buy one melon.”
“That’ll be one pound.”
The man hands over a pound and receives his melon. “I’d like to buy a melon.”
“That’ll be one pound.”
The man hands over a pound and receives a second melon. “I’d like to buy a melon.”
“That’ll be one pound.”
The man hands over a pound and receives a third melon, then begins to gesture towards his purchases. “Look, do you see what I just did?”
“Yes, you purchased three melons. No refunds, by the way.”


The joke is that he sold three melons, so the promotion works.
Probably written by AI.
How fucking dare you. I wrote this myself, thank you very much.
Don’t worry, OP. The joke was funny and creative.
I wouldn’t go that far, but it’s an unfunny, derivative joke written by a human.
Now hold on, it’s definitely not written by AI but I’ve seen this joke (or something very close to it) years and years ago. Retelling jokes is an art in itself that I certainly appreciate, but it doesn’t constitute writing them!
I will grant you that this is a good retelling of this one :)
I didn’t invent the joke, but I did write my retelling. If you’re going to be a pedant, you need to be correct, or you’ll end up with three melons you don’t need.