WASHINGTON — Donald J. Trump won the White House after spending a little more than half of what Hillary Clinton did, using a combination of his own money and contributions from donors big and small to fuel a campaign that shattered the modern conventions of money and politics.

The figures for the final weeks of the campaign, released late Thursday, showed that Mr. Trump paid his own companies nearly $12 million over the course of the election — reimbursement for flights, hotel stays, meals and services for him and his staff members, as well as office space in the tower he owns on Fifth Avenue in Manhattan. His preferred mode of transportation — his private aircraft — made up the largest chunk of money that went back into Trump entities, $8.7 million.

The figures also show that Mr. Trump put in $65 million of his own cash, well short of the $100 million he had originally promised he would spend on his campaign.

These unusual practices provide a glimpse of the kind of potential conflicts and ethical issues that Mr. Trump will have to resolve as president. The wealthiest man ever elected president, Mr. Trump is already facing calls from government ethics officials to sever ties to his vast real estate and financial holdings around the world. He is resisting so far, raising the possibility that he could enter office with a virtually unknowable number of personal entanglements that is without precedent.