Audition (Audio Editing)
Audacity (Mac/Windows/Linux)
Audacity is an open source, cross platform audio editor which is good for simple editing tasks, has VST plugin support for additional audio processing capabilities, and rudimentary multi tracking. You have to install free 3rd party add-ons to get AAC audio support.
Ocenaudio (Mac/Windows/Linux)
Free cross platform audio editor with a clean interface. Supports a lot of audio file formats, with decent audio processing, including support for Apple Audio Unit plugins on the Mac.
The following are not replacements for Audition, since they do quite a bit more. While they can be used for editing audio, they are Digital Audio Workstations (DAW) applications for music production. This includes extensive audio sample support, midi device control, plugins to extend audio processing capabilities and multi-tracking. Be prepared for a much steeper learning curve as a result. This is really a subset of many more of these type of applicatications; this list is focused on software that is very affordable or free.
Garageband (Mac)
Garageband is a free Mac only simple digital audio workstation application that comes with a fairly big sample library. It is oriented towards basic music production tasks, including basic audio recording and editing capabilities. Garageband projects can be imported into Apple’s more expensive, professional Logic Audio application and the corresponding Garageband application for iOS.
Ardour (Windows/Mac/Linux)
Ardour has a unique licensing model in that it is open source, but in that form only the source code is available (which has to be compiled). To get a compiled version (ready to use), you either pay a monthly licensing fee, which gives you periodic updates, or a one time pay-what-you-want cost (as little as $1.00) to get a current major release version. Available for Mac, Linux and Windows.
Podium Free (Windows Only)
Free multitrack audio production environment. Decent feature set with a similar interface to other DAWs.
http://zynewave.com/podium-free/
Tracktion Version 7 Free (Windows/Mac/Linux)
Tracktion offers a free version that is one of their older releases. It uses a unique “single screen” interface that some users like, but looks different than most DAW applications. Requires registration, but on the other hand, occasionally Tracktion will offer upgrades from Free versions to commercial versions at a discount.
Reaper (Windows, Mac, Linux)
Reaper’s pricing is unique in that they offer a $60.00 discounted price for individuals or educational use, and a more expensive license for higher end commercial use.
Avid Pro Tools First (Windows/Mac)
A free version of ProTools with several limitations. Up to 3 projects at any given time, which can only be saved to Avid’s cloud services.
http://apps.avid.com/ProToolsFirst/
Adobe Media Encoder
Apple Compressor ($49.99) (Mac)
Mac only, batch based video conversion tool primarily for MPEG-4, h264, Quicktime and MPEG-2 (such as for DVD mastering). Works as a standalone product or in concert with Final Cut X. Has come a long way in terms of user-friendliness, and the newest release is much faster.
https://www.apple.com/final-cut-pro/compressor/
Handbrake (Windows/Mac/Linux)
A free tool focused on video conversion. Simple user interface with handy presets for targeting web, mobile/tablet/computer and set top devices like the Apple TV or Roku box. The latest version has extensive device support.
Miro (Windows/Mac)
A free conversion application for Windows and the Mac. Has extensive file support with profiles for many devices or the web. Hasn’t been updated in awhile.
http://www.mirovideoconverter.com
AVIDeMux (Windows/Mac/Linux)
Swiss army knife for compressing/converting/manipulating video. While it is not the most user friendly application, it has a deep feature set.
http://fixounet.free.fr/avidemux/download.html
VirtualDub (Windows)
Capture/Edit/Manipulation for video. Mainly for working with AVI files. Editing is very basic, but there are some good options for manipulating video, and it is a nice, lightweight tool for capturing video.
VLC (Windows/Mac/Linux)
Open source, cross platform (Windows/Mac/Linux) media player that has media conversion capabilities baked in. It isn’t super user friendly for that task, but the built-in wizard helps somewhat with that.
After Effects
There are few direct replacements for After Effects which are affordable.
Motion ($49.99) (Mac)
Motion is similar to After Effects, but is focused on designing motion graphics, so lacks many features that After Effect has such as keying. But it’s still a powerful tool with a robust community, and good integration with Final Cut.
https://www.apple.com/final-cut-pro/motion/
Hitfilm 4 Express (Windows/Mac)
Compositor and Editor for Windows and Mac for free. Requires user to create an account, and link to social media account (“like” on Facebook, share via Google Circles, etc).
DaVinci Resolve (Fusion) (Mac/Windows/Linux)
Fusion is a component in DaVinci Resolve that does compositing and other functions. It uses a “node based” interface that takes a little time to master. There are both free and paid (Studio) versions of Resolve, the parent application.
https://www.blackmagicdesign.com/products/davinciresolve
Wax
A free Windows only video compositing tool. Hasn’t been updated in quite a while.
Premiere
There are three major editors that are used for professional work. They are Avid Media Composer, Final Cut and Adobe Premiere. Media Composer is fairly expensive. Final Cut X is $299.99, but is also part of a $199.00 education bundle which also includes Logic, Compressor, Motion and Mainstage (quite a deal). All have their proponents – Avid has been the go-to software for video editing for many years, particularly for the high-end film industry, while Final Cut and Premiere have matched (and in some ways surpassed) most of its features at a more affordable cost. What follows is a mix of professional and entry level tools.
Media Composer First (Free) (Windows/Mac)
Free limited version of Avid’s Media Composer for Mac and PC.
http://www.avid.com/media-composer-first#Overview-Download
iMovie (Mac)
A free, simple Mac only video editor. It is definitely not a Premiere replacement, but may suffice for basic video editing projects.
https://itunes.apple.com/us/app/imovie/id408981434?mt=12
Adobe Premiere Elements ($79.99 bundled with Photoshop Elements) (Windows/Mac)
Educational pricing is available, which drops the price. It is typically bundled with Photoshop Elements.
VideoPad (Windows/Mac)
Viideo editor that has both free and affordable paid options. It is similar to other timeline based editors – although a little more basic (which may be a good thing). You will have to poke around on their site a bit to find the link for the free version.
https://www.nchsoftware.com/videopad/index.html
DaVinci Resolve (Windows/Mac/Linux)
It’s ancestry is a professional color grading tool which has added full featured non-linear editing and more (Compositing, DAW). It is free and cross platform (Windows/Mac/Linux), although there is also a commercial version (called “Studio”) that includes features such as 4k video export support. Decent interface is somewhat similar to other timeline based editors, such a Premiere or older versions of Final Cut. It can adjust its interface based on what the user has used previously. Has significant hardware requirements for best performance but is worth checking out.
https://www.blackmagicdesign.com/products/davinciresolve
Lightworks
The non-pro version is free and cross platform, but you have to create an account with them. It doesn’t have lots of flashy effects; it is focused on editing. Free version is limited to 720p video and has other limitations.