As far as free stuff goes, and as far as not needing to visually step through your code and fancy stuff like that, just use a pretty-printing text editor. I used Kate back in KDE's 3.1 days, it was excellent (although I remember the odd quirk). I can only dream of Kate now. That sounds bad :) Plus JEdit isn't bad and Textpad is pretty cool too, you can set it up to execute your code and capture the output. There are probably too many excellent editors to list. I liked the idea of vi, but never bothered to get the hang of it.