So I assumed it would be, but yes, it is illegal to give people money to vote. 42 USCS § 1973i(c)
Under prohibited acts:
“…pays or offers to pay or accepts payment either for registration to vote or for voting shall be fined not more than $10,000 or imprisoned not more than five years, or both:”
I don’t know if Bloomberg could have just said, “I will give all of you $$$ if I’m elected.” That sounds like a fairly generic campaign promise.
Maybe gussy it up a bit? “If I’m elected, the US Government will give everyone a million dollars!” and then drop the appropriate amount into treasury.gov.
Edit: I used a million dollars because it’s a round number, but obviously Bloomberg didn’t and doesn’t have enough money to do that. Assume ~300 million US people. He’s got ~60 billion dollars. So $60,000,000,000 / 300,000,000 people > cancel some zeros > 60,000/300 $/person > $200/person. The population is actually north of 300 mil, and he’d run into huge liquefication losses if he tried. This is why the stock market capitalization numbers are silly. But even at max silliness, he has about $200/person, not millions.
FYI, anyone can pay more taxes than required if they want. On treasury.gov, you can click a button for donations to the US Treasury. So anyone who complains their taxes aren’t high enough could just pay more. I don’t think people do it too often.