Just a bit of quick math[0]:
~323,000,000 total US population
77.2% over the age of 18
~250,000,000 total over the age of 18
$12,000 per year per adult = $3,000,000,000,000 per year
[0] - https://www.census.gov/quickfacts/fact/table/US/PST045216
~323,000,000 total US population
77.2% over the age of 18
~250,000,000 total over the age of 18
$12,000 per year per adult = $3,000,000,000,000 per year
[0] - https://www.census.gov/quickfacts/fact/table/US/PST045216
UBI isn't like defense spending. It isn't a black hole you put tax dollars down and get nothing out. It means tremendous goods demand for the necessities of life that is extremely stable and reliable for businesses to profit off.
Unlike (some) defense spending, UBI doesn't intrinsically create some economic value. Increased stability would indirectly create economic value, but it needs to be more than the face value of the UBI check for it to not lead to gross inflation.
I feel it would drive a great de-urbanization, as people try to move places where they could get the most for their UBI.
Most people would pay $1000 more taxes per month and get it right back as $1000 in BI. The benefit would be that if their income suddenly fluctuates, that $1000 would be there as a baseline.
Personally, I'd love an extra 1k / month, but I rather see that go to a lot of other people before me.
The hard part is figuring out where to take the money to cover the difference.