In January, President-elect Donald Trump's transition team announced that the U.S.-Mexico border wall would be funded "through the appropriations process as soon as April." Nearly 100 days into office, one of Trump's biggest campaign promises faces major hurdles—and may never come to fruition.

According to CNN: "If Mexico refuses to pay for the wall, the GOP could add billions of dollars into the spending bill that needs to pass by April 28 to keep the government open."

Here are five of the wackiest ideas currently being considered to finance the wall's construction.

1. Undocumented immigrants

In an interview with ABC's George Stephanopoulos on Sunday, Attorney General Jeff Sessions insisted that undocumented Mexican immigrants living in the United States may be required to foot the bill for Trump's wall. 

"I know there's $4 billion a year in excess payments, accorording to the Department of the Treasury's own inspector general several years ago, that are [being paid] to people—tax credits that they shouldn't get,” Sessions said.

"Now, these are mostly Mexicans, and those kinds of things add up," he continued. "Four billion a year for 10 years is $40 billion. There are a lot of ways we can find money to help pay for this."

2. Canada

On Monday, President Trump announced new tariffs of up to 24 percent on Canadian softwood lumber products. The softwood lumber trade dispute between the U.S. and Canada has existed for over a century. Unlike Mexico and China, however, America’s second-largest trading partner has never been a prime target for Trump, until now. 

3. Corporations

GOP strategist Noelle Nikpour and Fox News host Brian Kilmeade devoted President Trump's favorite morning show to a brainstorming session. 

"If I were advising Donald Trump, I'm a national fundraiser, I would say, You know what, here's an idea, why don't you see if you can't get it privately funded?" Nikpour proposed. "Privately funded, meaning if you donate a certain amount—let's just say that the number is $12 billion to get this wall implemented, all right?"

"Or you could do it the fly-out-the-sponsor way," Kilmeade suggested. "This wall brought to you by Modell's. Or Aetna. Why not do it?"

Americans' growing disinclination to buy products endorsed by Trump is one very good reason why not. 

4. El Chapo

While initially dubious of Trump's wall plan, Sen. Ted Cruz (R-TX) has now introduced legislation to fund it. The Ensuring Lawful Collection of Hidden Assets to Provide Order, or EL CHAPO Act, "would repurpose $14 billion in assets the feds plan to squeeze out of [Mexican drug lord Joaquín 'El Chapo'] Guzman," the New York Post reported Tuesday. 

     5. Obamacare enrollees

President Trump's budget chief, Mick Mulvaney, wants to broker a deal with Democrats to prevent a government shutdown: Obamacare payments for wall funding. 

"We'd offer them $1 of CSR [cost sharing reduction] payments for $1 of wall payments," Mulvaney said during a Bloomberg Live interview.

The proposal was slammed by the Senate's top-ranking Democrat.

"The White House gambit to hold hostage health care for millions of Americans, in order to force American taxpayers to foot the bill for a wall that the president said would be paid for by Mexico is a complete nonstarter," said Matt House, a spokesman for Chuck Schumer. 

That was Friday. On Sunday, Trump lashed out on Twitter.