A person who knows the difference between right and wrong and chooses right is moral. A person whose morality is reflected in his willingness to do the right thing – even if it is hard or dangerous – is ethical. Ethics are moral values in action.

Interesting...

Do you take financial advantage of a vendors screwup to save a few bucks?

Do you alert the vendor to his error?

I think both the moral and ethical thing to do is to alert the vendor of his error.

I agree with Tim K. If a business owner errs on the billing, regardless of the direction, let him know.

Tim builds cabinets. If he charged $700 for a $7000 job, would you tell him his decimal is in the wrong spot? Or would you jump on it, hoping you got the deal of the century?

I guarantee it the decimal is in the other direction- $7000 vs $70,000, you'd make some noise.