Hollywood movie studios and the television industry now enjoy such a cozy relationship as wholly-owned subsidiaries of each other it is easy to forget that back at the close of Hollywood's Golden Age and the beginning of television's, the two were not close allies but bitter adversaries. The advent of television threatened Hollywood's life's blood revenue stream. Rental of films to movie theatres (preferably theatres the studios owned) was a key part of the economic model on which the old studio system was built. The studios did not want to play nice with the TV industry, but faced with anti-trust lawsuits (over the theatres) and competition from the hot new technology that made both sound and pictures fly through the air into the audience's living room, Hollywood eventually made peace with the new media kid on the block.
Consumer demand for TV sets and programming to watch on them had reached critical mainstream mass by the mid-50s. That helped convince the studios to swallow hard and start selling the television broadcast rights to what we now consider "classic films." The studios (through the syndication arms they created when they were forced to divest themselves of their theatres) sold packages of what were then just "old movies" directly to local TV stations, where movies were handy multitaskers. Stations drew an audience with films, but also relied on them as time-fillers, to--let's face it--give talent and crew a break when much of the broadcast day was still nearly all-live and mostly locally produced.
One of the most notable syndie packages was made up of horror films from Universal, including the original 1930s versions of Frankenstein and Dracula and other now-classic examples of the genre. By the late 1950s these films had spent up to 25 years gathering real dust (not a light atmospheric coating of fuller's earth from the prop department) in what was then Universal International's vault. The studios hadn't yet figured out that their vaults--their crypts, if you will--were about to become a new goldmine.
A station in what was at that time a medium-sized market of about 300,000 TV households might have paid $1000 per airing of an "A" movie with big stars, but as little as $300 per airing of a "B" western or a horror movie with little perceived value. That low dollar amount could be earned back by moving very little "inventory"--airing just a few commercials--and everything else was gravy.