You can purchase Winrar, but there is also the free 7-zip.
A free file archiver with the highest compression ratio. The program supports 7z, ZIP, RAR, CAB, ARJ, LZH, CHM, CPIO, RPM, DEB, GZIP, BZIP2, Z and TAR formats. Compression ratio in the new 7z format is 30-50% better than ratio in ZIP format. Also 7-Zip compresses to ZIP 2-10% better than PKZip and WinZip. 7-Zip has additional powerful command line version and FAR Manager support.
 

You can purchase Registry Mechanic, but there is also the free CCleaner.

A free, open source, cross-platform e-mail and news client. Easily organize and customize your mail. Thunderbird features many new enhancements to help you better manage your unruly inbox, and stay informed. Thunderbird scales to the most sophisticated organizational needs while making it easy to find what you need. Thunderbird allows you to customize your email to suit your specific needs whether it’s how you search and find messages or listening to music right out of your inbox. 
 

You can purchase Adobe Premiere, but there is also the free VirtualDub.
VirtualDub is a video capture/processing utility for 32-bit and 64-bit Windows platforms (98/ME/NT4/2000/XP/Vista/7), licensed under the GNU General Public License (GPL). It lacks the editing power of a general-purpose editor such as Adobe Premiere, but is streamlined for fast linear operations over video. It has batch-processing capabilities for processing large numbers of files and can be extended with third-party video filters. VirtualDub is mainly geared toward processing AVI files, although it can read (not write) MPEG-1 and also handle sets of BMP images.
 

You can purchase ACDSee Photo Manager, but there is also the free IrfanView.

IrfanView is a very fast, small, compact and innovative freeware (for non-commercial use) graphic viewer for Windows. It is trying to be simple for beginners and powerful for professionals. IrfanView is always trying to create new and/or interesting features in its own way.
 

You can purchase Kaspersky Antivirus, but there is also the free Avira Antivir Personal.

Avira AntiVir Personal is a comprehensive, easy to use antivirus program, designed to offer reliable free of charge virus protection to home-users only. Avira AntiVir Personal offers: - Extensive recognition of malware and viruses, Trojans, backdoor programs, worms, etc. - AntiAdware/AntiSpyware: eliminates adware and spyware. - Automatic incremental updates of antivirus signatures, engine and software. - Permanent virus protection, with Virus Guard real time monitoring. - Virus protection against known and unknown threats, using an advanced heuristic system - AHeAD. - Scheduler where you can set the scanner to make automatic virus scans or updates on your system.
 

You can purchase G DATA InternetSecurity, but there is also the free ZoneAlarm Firewall.
ZoneAlarm Free Firewall blocks hackers from infiltrating your home PC by hiding your computer from unsolicited network traffic. By detecting and preventing intrusions, ZoneAlarm Free Firewall keeps your PC free from viruses that slow down performance, and spyware that steals your personal information, passwords, and financial data.
 

You can purchase Nero, but there is also the free Deepburner.
DeepBurner is an advanced and extremely powerful CD and DVD burning package that comes absolutely for FREE. It removes the hassle of making CDs, DVDs, and autoruns. It even makes it easy for you to create and print your own labels and booklets. DeepBurner supports a very wide range of internal and external (USB 2.0 and FireWire) CD and DVD writers. Burn any data, copy any disc, make backups, make ISO CDs with this very easy to handle software!
 

You can purchase PowerDVD, but there is also the free VLC Media Player.
VLC media player is a highly portable multimedia player for various audio and video formats (MPEG-1, MPEG-2, MPEG-4, DivX, mp3, ogg, ...) as well as DVDs, VCDs, and various streaming protocols. It can also be used as a server to stream in unicast or multicast in IPv4 or IPv6 on a high-bandwidth network. It doesn't need any external codec or program to work.
 

You can purchase Microsoft Office, but there is also the free LibreOffice.
LibreOffice is a powerful and free office suite, a successor to OpenOffice(.org), used by millions of people around the world. Its clean interface and feature-rich tools help you unleash your creativity and enhance your productivity. LibreOffice includes several applications that make it the most versatile Free and Open Source office suite on the market: Writer (word processing), Calc (spreadsheets), Impress (presentations), Draw (vector graphics and flowcharts), Base (databases), and Math (formula editing).
 

You can purchase Adobe Photoshop, but there is also the free Paint.net.
Paint.NET is free image and photo editing software for computers that run Windows. It features an intuitive and innovative user interface with support for layers, unlimited undo, special effects, and a wide variety of useful and powerful tools. An active and growing online community provides friendly help, tutorials, and plugins.
 

You can purchase Magix Music Maker, but there is also the free Audacity.
A fast multi-track audio editor and recorder for Linux, BSD, Mac OS, and Windows. Supports WAV, AIFF, Ogg, and MP3 formats. Features include envelope editing, mixing, built-in effects and plug-ins, all with unlimited undo.
 

You can purchase VMware Workstation, but there is also the free Virtual Box.
VirtualBox is a general-purpose full virtualizer for hardware. Targeted at server, desktop and embedded use, VirtualBox is now the only professional-quality virtualization solution that is also Open Source Software.