Republican presidential nominee Donald Trump has run an unusually cheap campaign in part by not paying at least 10 top staffers, consultants and advisers, some of whom are no longer with the campaign, according to a review of federal campaign finance filings.

Those who have so far not been paid, the filings show, include recently departed campaign manager Paul Manafort, California state director Tim Clark, communications director Michael Caputo and a pair of senior aides who left the campaign in June to immediately go to work for a Trump Super PAC.

The New York real estate magnate and his allies have touted his campaign's frugality, saying it is evidence of his management skills. His campaign's spending has totaled $89.5 million so far, about a third of what Democratic rival Hillary Clinton's campaign has spent.

But not compensating top people in a presidential campaign is a departure from campaign finance norms. Many of the positions involved might typically come with six-figure annual paychecks in other campaigns.