For $1000, Rand Paul will autograph a copy of the Constitution for you.

Inside the topsy-turvy world of presidential campaign book economics:

Based on the $122,000+ that Cruz’s campaign paid HarperCollins, and considering the $27.99 retail price and the typical author discount of 50%, the Cruz campaign likely purchased 8,000-10,000 copies of A Time For Truth. That’s a hefty profit for HarperCollins and a huge profit for Cruz if the campaign is able to sell those copies ['autographed'- ed.] at $85 a pop. In essence, the campaign is taking money from Cruz’s donors to buy books, many of which they will sell right back to those donors at a massive markup.

Yet, despite the ethical gray area, this may just be how campaigns are expected to fund themselves. Says CNN contributor and syndicated conservative columnist S.E. Cupp: “The idea of public service certainly takes a hit when lining one's own pockets becomes at the very least a side-job of running for President. But as a book author and a capitalist, I fail to see the issue.”

This is hardly the first time a presidential candidate—or sitting president—has come under scrutiny for questionable book purchases. In 2011, Herman Cain’s campaign was found to have purchased $36,511 worth of Cain’s books from the candidate’s private motivational speaking company. Conservative commentator George Will called Cain an “entrepreneurial charlatan” and said he "used [his campaign] as a book tour, in a fundamentally disrespectful approach to the selection of presidents.”

According to a former senior policy advisor to a presidential candidate, “Every campaign wants to tout their candidate as a #1 New York Timesbestseller. And campaigns will do whatever is possible to try to get that top spot, or raise the book two or three spots. And buying books in bulk is part of that.”

Ben Carson, running second to Donald Trump in most polls, recently suspended his campaign to embark on a tour to sell his new book A More Perfect Union. But he’s already running into trouble, as his publisher, Sentinel, is footing the travel bill, even though Carson’s book events seem closer to campaign events than book signings. He drew over 2,000 supporters to a signing at Books-A-Million in San Antonio—and participated in a brief Q&A with reporters—without having to deplete his war chest.  Carson’s campaign website offers (unsigned) copies of his booksMy Life and Gifted Hands for $20—markups from their respective retail prices of $2.99 and $7.99.

In 2010, while on tour for his book No Apologies, Mitt Romney rejected traditional speaking fees, asking that organizations instead purchase the equivalent number of copies of his book. No Apologies landed atop the New York Times bestseller list—albeit with an asterisk denoting bulk sales.

In 2011, the government’s online procurement database revealed that the State Department had spent over $70,000 purchasing copies of President Obama’s books to be used as Christmas gifts and to stock foreign embassies, including $40,000 worth of Dreams From My Father for the U.S. embassy in Cairo. This equates to several thousand copies earmarked for that single embassy.

Using campaign funds to purchase a candidate’s own books is perfectly legal, however the legality of selling them has changed. In 1996, the FEC stated that Senator Al D’Amato could gift the book to donors or fundraisers, but only sell them if the book were self-published. Yet when Scott Brown instigated an FEC ruling for purchases of his book Against All Odds, it was ruled that he could resell the books. The FEC declared that candidates must purchase the books at fair market value (defined as “a bulk rate that is a standard fair market price that the Publisher, under normal industry practice, makes available on equal terms to other large purchasers.” That fair market price usually equates to a discount of around 50%).

And writing books can be quite a lucrative endeavor for politicians—and a chance to travel around the country while courting potential voters on the publisher’s dime. Marco Rubio received $800,000 from Penguin for An American Son. Hillary Clinton got millions for Hard Choices. And because Clinton’s book was released before she declared her candidacy, she did not have to dip into campaign funds for travel expenses. Those were footed, again, by her publisher.

Neither Rubio nor Clinton sells signed copies of their books on their campaign websites...