Get one of those credit cards with zero interest for like 10 years, and a limit of 5 trillion dollars.
The Federal Reserve could actually do that. And as existing debt matures, it would lower the interest payments the federal government pays in the future. We paid $404 billion in interest last year.
I'm not sure what effect it would have on the financial markets, if the US federal government isn't issuing new debt at market rates.
"The federal debt at the end of the 2018/19 fiscal year (ended September 30, 2019) was $22.7 trillion. The portion that is held by the public was $16.8 trillion. Neither figure includes approximately $2.5 trillion owed to the government.. Interest on the debt was $404 billion." - wikipedia
It would also have a negative effect on trust funds like Social security and Medicare that invest in US Treasuries. But that would be a wash from a whole of government view.