Photoshop and Illustrator are great graphic programs but come with a high price. Even the educational versions cost a great deal if you are outfitting a media lab. Photoshop can be replaced by the free Gimp. Inkscape can fill in for Illustrator.
Inkscape. Draw Freely: "Inkscape is a Vector Graphics Editor, similar to Adobe Illustrator, that strives to be SVG Compliant, open source, responsive and extensible."