Open source applications and tools are a great alternative for those on a budget. Many open source tools have comparable features to the expensive applications, and are also free. This makes it possible to have all the tools and applications without even spending any thing!
Editors
Notepad++
Notepad++ is a source code editor and Notepad replacement that supports several languages. It runs on Windows and is governed by a GPL License.
jEdit
jEdit is a cross platform text editor with hundreds of person-years of development behind it.
Quanta Plus
Quanta Plus is a highly stable and feature rich web development environment.
Aptana Studio
Complete web development environment that combines powerful authoring tools for HTML, CSS, and JavaScript, along with thousands of additional plugins.
KompoZer
KompoZer is a complete web authoring system that combines web file management and easy-to-use WYSIWYG web page editing.
Firebug
Firebug is a plugin for Firefox that allows you to edit, debug, and monitor CSS, HTML, and JavaScript live in any web page.
Graphics Applications
GIMP
GIMP is a versatile graphics manipulation package. It’s considered by many to be an excellent alternative to Photoshop.
Krita
Krita is a graphics application for everyone who wants to get creative with images.
Inkscape
Inkscape is a vector graphics editor, with capabilities similar to Adobe Illustrator.
Dia
Dia is a cross operating system diagram creation application.