Origin
It was used in this way by Joseph Addison in The Spectator (1712): “A woman who will give up herself to a man in marriage where there is the least room for such an apprehension…may very properly be accused…of being penny wise and pound foolish.” [c. 1600]
Explanation
It means to be extremely careful about small amounts of money and not careful enough about larger amounts of money. Someone who is penny wise, pound foolish can be very careful or mean with small amounts of money, yet wasteful and extravagant with large sums. This phrase alludes to British currency, in which a pound was once worth 240 pennies, or pence, and is now worth 100 pence. The phrase is also occasionally used for being very careful about unimportant matters and careless about important ones. Everyone loves saving money, cutting back, and reducing expenses. However, sometimes there is a tendency to focus on the wrong things. While you’re busy feeling good about reducing little costs here and there, every once in a while you neglect the larger picture.
Example
Education budget cuts are penny wise and pound foolish public education is an investment in our future.