I'm assuming you're asking how much it costs and how to go about leasing a 35mm film for public exhibition. You need to find out the theatrical distributor for the film you're interested in. You can start with a company called Swank Motion Pictures and they might be able to recommend who you need to talk with. Films are rented for exhibition based on the number of times you want to show it and for specific dates. There's a base fee and usually they'll take a cut of the box office. An older film might be rented for $100-$200 per showing plus box office; others might be much more ($1,000 and up) per showing. Keep in mind that not all films are available. Even more recent (ie, past twenty years) films may not have circulating 35mm prints - the studio may have taken them out of circulation because of a lack of interest or they might not have film prints in good enough condition for rental and aren't making new ones of a title because of declining rentals. Some films are available for rental on DVD, which is a popular format for exhibition in non-theatrical settings, such as colleges and universities. (Of course, you cannot just rent or buy a DVD and show it publicly without permission from the studio or copyright holder.)