Inscape
Alternative to: Illustrator
Price: Free
Platform: Windows 7/8

ScribusFree Software alternative to CC for students list,
Alternative to: InDesign
Price: Free
Platform: Windows 7/8

Synfig
Alternative to: After Effects, Flash
Price: free
Platform: Mac OS X 10.7.5

Google Web Designer
Alternative to: Photoshop and Edge Animate for web graphics and design.
Price: free
Platform: Mac OS X 10.7 or later, Windows 7/8

GIMP 2.8.14
Alternative to: Photoshop
Price: free
Platform: Mac OS X 10.9, Windows XP/Vista, GNU/Linux

Blackmagic Fusion
Alternative to: After Effects for VFX
Price: Free
Platform: Windows 7/8

Unubantu Studio
Alternative to: After Effects, Flash
Price: free
Platform: Linux

If you have a bit of a budget

Affinity Photo
Alternative to: Photoshop
Price: £39.99
Platform: Mac OS X 10.7.5