Is there a limit to how many times a person can run for president?

Nope, as long as you make sure you don't win, you can run for President as often as you want. And the nice thing is that according to federal Law as long as you are running you can pay yourself(out of campaign donations) the expected salary of the office you hold. One person who perfected this scam of being a perpetual candidate is Christine O'Donnell but she only ran for House Seats.