Actually Lisp systems were no more expensive than other advanced language implementations. But one needed a bunch of expensive RAM. At that time there were alr

Actually Lisp systems were no more expensive than other advanced language implementations. But one needed a bunch of expensive RAM. At that time there were already free implementations of Common Lisp for Unix: AKCL (later GCL), CMUCL, CLISP, XLISP, ... IDE for those were usualy GNU Emacs or Xemacs with ILISP. Windows had less choice for free implementations, but one used the commercial implementations anyway and some were not that expensive. On the Mac everyone used Macintosh Common Lisp - which at some point was owned and sold by Apple itself - not very expensive.