I'm sure you've heard this before, but I'll do some back of the envelope math. I'm getting all my numbers from: https://taxfoundation.org/summ....
Total taxes paid: 10.2T
Taxes paid by the one percent: 3.8T
Effective tax rate on the one percent: 26.9%
Total adults in USA: 209,000,000
Give everyone $1000/month
Total cost: 2.5T
Total wealth of the one percent: 3.8T/.269=14.1T
To afford a 1K a month UBI, we just need to tax the one percent enough to pay for it:
3.8T+2.5T=6.3T
6.3T/14.1T=.447
It seems like that if you tax the richest one percent of Americans at 44.7% and you will pay for $1000/month for every American over 18, without adding any burden to the 99%.
Of course, this doesn't take into account the savings for getting rid of all other forms of federal welfare. And, if you put more effort into this, you design it so that anyone making around $100,000 (or something) pays $12000 in higher taxes than they do now, and gets back $12,000 dollars from UBI. So they net zero. If you make more than that, you're paying into helping folks who need it. If you make less you're benefiting.
Ideally, UBI replaces all other forms of welfare and acts as an absolute security net for all Americans. No one is quitting their job for $1000/month (or at least, very few people are). It just means that if things go suddenly bad, you don't have to worry about dealing with signing up for welfare or whatever.
Also, implementing universal, single payer healthcare would be a huge step forward as well, and is much more important than UBI. Right now there is an industry (the insurance industry) that acts as a middle man. They contribute nothing and only act to siphon off money.