Full GUI suite for rapid game prototyping to full-scale production. Free to try for 30 days.

Simple and quick 3D programming language. Free to try (limited source file size).

Open source graphics rendering engine. Free under LGPL!

Lightweight open standards 3D programming language. Free!

Graphical X3D editor by MediaMachines. Free!

Robust and affordable game development solution. Develop for XBox and Wii as well as PC. Indie license: $150.

Well, not really. An Unreal Engine 2 license runs for $350,000, but the Unreal Runtime, built on the Unreal Engine 2, allows students to experiment with the Unreal editing suite. Development of games for distribution is not permitted. Free.

Excellent, open source 3D modeling tool. Very powerful, very free.

DTS exporter scripts for Blender.

DTS exporter for Maya.

DTS exporter for 3DS Max.

QuArK is a BSP brush editor, and a free alternative to GarageGames' Constructor. This is a tool used to create interiors only. This link is to Ken Finney's custom installer to easily set up QuArK for Torque.

A modeling package specifically for low-polygon gaming models. Import/export support for Torque, Half-Life, GameStudio, Kingpin, Jedi Knight, Doom3, Call of Duty, and many others. This is shareware, and free to evaluate for 30 days.

An open source Photoshop alternative. Built off the Gimp core, this package, written by Scott Moschella, is designed mimic the Photoshop experience. Also free.

Open source audio recording/editing software.