Donald Trump’s campaign is auditing axed campaign manager Corey Lewandowski’s decision to buy T-shirts and other political swag from a pal’s Colorado-based company, campaign sources told The Post.

Federal records show Trump’s campaign paid $2.1 million to WizBang Solutions, a company based in a Denver suburb. The firm billed the campaign for printing T-shirts, “Make America Great Again” caps, yard signs, note cards and flyers, as well as postage and design costs nearly every month since April 2015, the records show.

WizBang’s director, Mike Ciletti, is a longtime friend and former client of Lewandowski, having provided printing services for conservative group Americans for Prosperity when Lewandowski worked for it.

Ciletti visited Trump Tower several times last summer and launched a super PAC, the Make America Great Again PAC, promoting Trump’s campaign, according to a Washington Post report.

Lewandowski first denied knowing Ciletti but later acknowledged he “knew of” him and did not say whether he hired him, WaPo reported.

When a reporter called WizBang and asked who at Trump HQ hired the company, an employee replied, “I am not allowed to say anything.”

As the campaign’s costs climbed, Trump officials complained they were paying WizBang about $8 per T-shirt, a source said. Lewandowski blew up when the officials suggested choosing a firm that could print shirts at one-fourth the price, the source added.

The spending caught the eye of campaign chairman Paul Manafort, who performed a review when he joined Team Trump in March. Manafort later ordered an audit led by Trump’s top business confidante, Allen Weisselberg, the sources said.

But Lewandowski allegedly wouldn’t cooperate.

Trump fired Lewandowski on June 20. The audit was not a factor, the sources said.

A Trump spokeswoman denied the existence of the audit.

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