Rounding errors

So the Post Office is considering raising the price of a stamp to 39 cents. Fine, fine.

But tell me this — why the heck can’t they ever pick a round number? What’s wrong with 40 cents?

I think the Post Office’s stamp machines are the only vending machines on earth that have to give pennies as change, for the folks who buy one or two stamps. How much extra does that cost?

Sheesh!