In the store the sign on the box of frozen chicken legs and thighs said seventeen pesos per kilo, but when I checked the label on my bag, I had been charged twenty one.
Not a great difference, to be sure, but it was the principle of it that made me call attention to this and get the price altered.
On the bus home from this shopping, a young kid with malformed hands were singing, loudly and off key, to make money for an operation he said.
I gave what I had gained from pointing out the difference in prices, and then some.
This was money well spent.