Who says "20 cent"?
When I worked at a mall kiosk (lottery/convenience store kind of place), I was amazed at the number of times I heard people say 10, 20, 30, (and so on) cent. I didn't know them personally, but I did witness this A LOT. What would happen was they would be short the change for the items they were paying for and they'd ask their shopping partner for 20 cent (or whatever) instead of 20 cents. They would say things like "you got 20 cent" or "I need 20 cent."
I'm not sure how I would categorize this sect of people though. It was more an attitude than anything else.
I don't blame you for asking because who would really say that? It happens though. I promise you. It used to really irk me because surely it doesn't take that much more effort to say "cents" instead of "cent."