Ted Haggard quote: “How much is your sin going to cost me?”

“They charged me 15 dollars. That's how much it costs to only have 20 dollars.”

Louis C.K. (1967) American comedian and actor

On being broke http://youtube.com/watch?v=rpaCQKJpE9k

“If I knew in 1986 how much it was going to cost to keep Pixar going, I doubt if I would have bought the company.”

Steve Jobs (1955–2011) American entrepreneur and co-founder of Apple Inc.

As quoted in Fortune (18 September 1995)
1990s

“To regret your sins of commission as much as your sins of omission is to prove yourself a most unworthy sinner.”

Elizabeth Bibesco (1897–1945) writer, actress; Romanian princess

Haven (1951)

“Posterity: you will never know how much it has cost my generation to preserve your freedom. I hope you will make good use of it.”

John Quincy Adams (1767–1848) American politician, 6th president of the United States (in office from 1825 to 1829)

Attributed in The Rebirth of a Nation : With a Bill of Rights for America's Third Century (1978) by Robert S. Minor, p. 10; this is a paraphrase of a statement by his father John Adams in a letter to his mother Abigail Adams (27 April 1777): "Posterity! you will never know how much it cost the present generation to preserve your freedom! I hope you will make a good use of it. If you do not, I shall repent in Heaven that I ever took half the pains to preserve it".
Misattributed

“How much do you think it costs to go to college? Most people are likely to answer by adding together their expenditures on tuition, room and board, books, and the like, and then deducting any scholarship funds they may receive. Suppose that amount comes to $15,000.
Economists keep score differently. They first want to know how much you would be earning if you were not attending college. Suppose that salary is $20,000 per year. This may seem irrelevant, but because you give up these earnings by attending college, they must be added to your tuition bill. You have that much less income because of your education. On the other side of the ledger, economists would not count all of the university’s bill for room and board as part of the costs of your education. They would want to know how much more it costs you to live at school rather than at home. Economists would count only these extra costs as an educational expense because you would have incurred these costs whether or not you attend college. On balance, college is probably costing you much more than you think. And, as we will see later, taking opportunity cost into account in any personal planning will help you to make more rational decisions.”

William J. Baumol (1922–2017) American economist

William Baumol and Alan Blinder, Economics: Principles and Policy (2011), Ch. 1 : What is Economics?