In the TV arena, this is a fee that TV studios or networks pay an agency when they purchase a TV series. This fee is to compensate the agency for attaching all the key auspices for a television series. This includes an upfront fee they get as soon as the show is purchased, and a back-end percentage (usually around 10 percent) for any gross profits the show generates. Most of the time, only one agency receives the package fee, but on the rare occasion, if two agencies attach to big pieces of talent onto a series, they will split the package fee.
Furthermore, any clients of that agency that are working on that show do NOT have to pay their agency commission because it’s a show that their agents packaged. For example, you’ll often hear that a TV show is a “WME package”. This simply means that the show was packaged by WME before selling to the studio.