The Secret Service dropped at least $471,000 in taxpayers’ money at Donald Trump’s companies between his inauguration month and April 2018, according to a stash of over a hundred receipts compiled by The Washington Post that lay bare an unprecedented business relationship between a sitting president and his own government.

Trump’s company has previously insisted that it always charges friendly rates to Secret Service staff when they are made to accompany the president to his properties—but the Post’s cache of receipts casts a whole lot of doubt on that. For example, at Mar-a-Lago, the Secret Service was reportedly charged $650 per night dozens of times in 2017, but was given a different and cheaper rate of $396.15 other times in 2018.

Another staggering bill was reportedly presented to the Secret Service for the privilege of staying at the Trump National Golf Club at Bedminster, where it was charged $17,000 a month to use a cottage on the New Jersey property in 2017. That’s several times above the standard rent in the area, and Trump was reportedly only there a third of the time during the billed month.

NBC News previously reported, in June of last year, that the Trump International Hotel in Washington charged the Secret Service more than $200,000 in taxpayer money from September 2016 to February 2018. That’s despite the fact that, unlike in Mar-a-Lago and Bedminster, Trump hasn’t spent a single night there since he took office back in 2017.

Federal conflict-of-interest rules don’t apply to the president, and the Secret Service doesn’t have hotel-room spending limits, so there’s nothing stopping Trump’s company from charging whatever it wants.

Even though it’s one of the deepest insights into Trump’s business relationship with his government so far, the Post reports that its compiled receipts it has managed to gather likely undersell the true amount of taxpayers’ money that’s changed hands from the Secret Service to the Trump Organization.

The Secret Service has failed to list all of the receipts in public databases of federal spending, which is normally required for payments of more than $10,000. The public receipts only cover a small sample of Trump’s travel during part of his term, so the $471,000 total is likely to be a fraction of the true amount of money the Secret Service has paid to Trump properties.

Despite that, the receipts do show that some statements from the Trump Organization have been misleading. In an interview with Yahoo Finance last year, Trump Organization Executive Vice President Eric Trump said: “If my father travels, they stay at our properties for free... If he stays at one of his places, the government actually spends, meaning it saves a fortune because if they were to go to a hotel across the street, they’d be charging them $500 a night, whereas, you know we charge them, like $50.”

In a new statement given to the Post about the receipts, Eric Trump said: “We provide the rooms at cost and could make far more money renting them to members or guests.” However, Eric didn’t say how the company arrives at its “at cost” price for the Secret Service, which the receipts show varies and has been as high as $650 a night.

Jordan Libowitz, of the watchdog group Citizens for Responsibility and Ethics in Washington, said: “That’s kind of crazy that we know the president is benefiting from the presidency, and we do not know how. We do not know how many taxpayer dollars are in his pocket.”

In a statement, the Secret Service said its spending “balances operational security with judicious allocation of resources.”