One of the variety languages I used in my CS undergrad in the late 1980s. From what I remember this included at least PL/1, 6809 assembly, C, Pascal, Fortran, Modula-2, and Scheme.
$50 sounds right. My recollection from ca. 1991 was that a guy in Texas sold Modula-2 for about that. It would run on an XT.