Is it ensure, insure, or assure?
1. An early, barely-functional version of a program which can be used for demonstration purposes as long as the operator uses *exactly* the right commands and skirts its numerous bugs, deficiencies, and unimplemented portions.
2. A special version of a finished program (frequently with some features crippled) which is distributed at little or no cost to the user for enticement purposes. See crippleware.