I think I was called a liar this morning

But I did laugh.  After I was safely in the back room out of earshot of customers.
I was putting some more reduced items on our produce reduced rack as an older couple were walking away.  The man said to his wife "Hey, she has bags of mushrooms."  So, they turned back.  The woman picked up a bag from my cart and turned it over in her hands.
Her:  "How much?"
Me:  "They would be $4.40 a kilogram...that's about $1.99 a pound."
Her:  "THAT'S not half price!"
Me:  "Actually, the regular price is $8.80 a kilogram, or $3.99 a pound."
She looked at me with what looked like a mixture of disgust and anger on her face.
Her:  "IT IS **NOT**!"
She put the bag down and walked off.  I walked off too, after I finished at the reduced rack, and laughed as I told a fellow employee about my encounter.  His response?  "They're $8.80 a kilogram?  Since when?" (Okay, so he hasn't been paying much attention to the mushroom price over the last few months either!)
Uh...I may not always remember what on earth day it is, and I may sometimes fib a little about my age (but when pressed, I do reveal my true age), but I've been bagging up reduced mushrooms several times a week, and they HAVE been $8.80 kg/$3.99 lb for weeks now. 
It makes me wonder if she's someone who shops with total disregard for how much produce really is...until there's a 50% off sticker slapped on, THEN they're aware of the price.
Honestly, I did feel a bit sorry for her, I think I burst the bubble of denial over high prices she'd been living in.