There is no legal limit, but parties have somewhat limited resources.
20 dollars a day
1968
1968
1968
The electors are committed to a certain candidate. Their vote is a matter of pubic record. It is not likely that they will contrary to their party.
Former President Theodore Roosevelt created the Progressive Party (nicknamed the "Bull Moose Party") after he failed to receive the Republic nomination in the 1912 presidential election. Theodore Roosevelt received 88 electoral votes and 4,119,207 (27%) of the popular votes.
Roosevelt was a candidate for the Progressive's Bull Moose Party.
Theodore Roosevelt was the Republican Party candidate in 1904 and the Progressive Party candidate in 1912. That was the last time the candidate of a party other than the Republican Party or the Democratic Party came in 2nd in a U. S. Presidential election.
The Whig Party had lost much of its power by 1856, and at their national convention in September of that year they chose not to put up a candidate of their own for president but rather to endorse the American Party's candidate, Millard Fillmore.
candidate
Straight Party voting is voting for the candidate of a certain political party for every office on an election ballot that has a candidate of that party.
the minor party candidate is likely to draw votes from the opposition.