Jim Knopf, nicknamed Jim Button ("Knopf" meaning "button" in German), is considered by many to be one of the "fathers" of shareware (so named by fellow software veteran Peter Norton). He released his first program, PC-File (a flat file database), in late 1982 as "user supported software". He has been quoted as saying this expression not only reflected the optional payment model, but also that comments from users drove the development of later releases. Wikipedia
The definitive Wikipedia entry for Jim Knopf. Wikipedia is the biggest multilingual free-content encyclopedia on the Internet. en.wikipedia.org/wiki/Jim_Knopf
For two programmers, Andrew Fluegelman and Jim Button, the idea of letting people try their software before they paid for it, came at almost the exact same point in time. www.paulspicks.com/history.asp