Unlike other cable networks, premium services are almost always subscribed to "a la carte", meaning that one can, for example, subscribe to HBO without subscribing to Showtime (in Canada, there are slight modifications, as most providers include U.S. superstations – such as WGN-TV and KTLA – with their main premium package by default). However, subscribing to an "individual" service automatically includes access to all of that service's available multiplex channels and, in some cases, access to content via video-on-demand (in the form of a conventional VOD television service, and in some cases, a companion on-demand streaming service as well). Most pay television providers also offer a selection of premium services (for example, the HBO, Showtime and Starz packages) in one bundle at a greatly reduced price than it would cost to purchase each service separately, as an inducement for subscribers to remain with their service provider or for others to induce subscribers into using their service. Similarly, many television providers offer general interest or movie-based premium channels at no additional charge for a trial period, often one to three months, though there have been rare instances of free trials for pay services that last up to one year for newer subscribers to that provider's television service.