Trump spent $55K in campaign money to buy his own book — which is probably illegal

Donald Trump may have broken the law by using campaign donations to buy thousands of copies of his own book at retail cost.

His campaign raised eyebrows this week when a filing with the Federal Election Commission revealed a $55,055 expenditure on May 10 to Barnes & Noble, but The Daily Beast reported that money was used to artificially boost sales for Trump's latest book and line the candidate's pockets with donor money.

The expenditure amounts to more than 3,500 copies of the hardcover version of Crippled America: How to Make America Great Again, or more than 5,000 copies of the retitled paperback version, Great Again: How to Fix Our Crippled America.

Related: Trump campaign spends $55,000 at Barnes and Noble and the internet has some ideas on what

A Trump spokesperson told the website the books were purchased as gifts for attendees at the Republican National Convention -- which the representative said the campaign was required to do.

"Sure enough, delegates in attendance at the Republican National Convention in Cleveland in July were given canvas tote bags, stamped with the Trump slogan, and filled with copies of Crippled America, as well as Kleenex and Make America Great Again! cups, hats, and T-shirts," reported The Daily Beast. "Delegates were also given plastic fetus figurines."

The Republican National Committee did not respond to requests to confirm that Trump or his campaign were required to spend more than $50,000 to buy copies of the nominee's own book.

Trump's campaign refused to confirm on the record to The Daily Beast whether the real estate developer and reality TV star had accepted royalties from the sales -- which would have broken campaign laws.

"The bottom line is, no money of this $55,000 from the book can end up in Donald Trump’s pocket without violating federal law," said Paul Ryan, of the nonpartisan nonprofit Campaign Legal Center.

The publisher, Simon & Schuster, did not respond to requests for comment.

A spokesperson for Hillary Clinton's campaign told the website that the Democratic nominee's representatives had probably purchased a few copies of her own books for office use, but never in bulk.

The bulk purchase may have been an unsuccessful attempt to put Trump's book on the New York Times bestseller list, which calculates retail purchases from brick-and-mortar shops like Barnes & Noble but not sales made through Amazon or directly from the publisher.

Other FEC filings have shown the GOP nominee has spent millions of dollars in campaign money to travel by a private airline owned by Trump, and he also spends campaign money at buildings and restaurants he owns.

A Huffington Post report on Monday found Trump had raised the rent 500 percent on his campaign headquarters at Trump Tower in Manhattan once he started receiving campaign funds from the Republican Party.

The Trump campaign later defended the price hike, saying the price hike was the result of adding more office space to accommodate future expansion.