Any amount will call for a personalized thank you, but for just $25 you immediately get your name stamped in the "Thank You" credits of the film. It takes a lot of people to support a film like this and we want to show our gratitude.
You are out of control! Support like yours calls for an "Associate Producer" credit. This leads to an IMDb credit (or page if it's your first) and invitation and involvement with all elements of the film -- to shooting, screenings, premieres, etc.
Are you an actual deity? Where did you come from? We won't ask anymore questions and gratefully hand the title of "Executive Producer" to you -- a major IMDb credit. You made our movie! Invitation to join us in everything related to the film, every step of the way. Plus, you get every other previous reward.