What an odd term, stock music. What does it mean? What does it refer to? Why would anyone ever need something of this sort? These questions and more are what pops into the minds of some when reading that term.
What it is is this: It is music that can used by used in movies, television, commercials and the like. It is a way to avoid using popular music that could come with huge royalties and fees. This isn’t to say that the music is free, only that the gigantic fees are not there.
Typically an interested person would find a royalty free source by searching for one on a search engine. There are several companies out there specializing in this type of thing (of course they would ultimately land at Productiontrax). Each site has its own pricing details. Some require a small fee for each clip or tune purchased. Others require a fee for a membership and the level of the membership dictates how many sounds or songs one might able to use form the site in a given period of time (like each month). When selecting a stock music service, beware of the fees and license restrictions that each site places on their music.
The person utilizing the music is then free to use it in public displays like movies, television shows, commercials (both television and radio) and more. These songs and clips are tunes that are not copyrighted, like jingles, but similar to the noises heard right before the bad guy kills the girl trapped outside in the B rated horror movie. This is a great way to keep costs down but still be compliant with copyright laws and restrictions.