Trump is not the first President to be arrested. Ulysses S. Grant was arrested in 1872 for speeding in a horse-drawn carriage. He posted $20 bail.
https://www.nytimes.com/2023/04/04/nyregion/ulysses-grant-trump-arrest.html
Ulysses S. Grant Was the First President to Be Arrested

Ulysses S. Grant, who had an eye for spirited horses and an apparent yen to test their mettle, was arrested in 1872 for speeding on a street in Washington.

The New York Times