When shopping around for cheap software it is important to know that all software is not created equal. There are thousands of software retailers you will find on the internet that have really nice websites and claim to have authentic software, but in reality are selling pirated, unlicensed versions of software that are both illegal for them to sell and just as illegal for you to purchase and use.
Two ways to tell for sure that software is not on the up and up is if they say it is OEM software or software that you can download from a source other than the maker of the product.
No major software manufacturer is going to let someone else sell downloads of their product. The only place you can get legal, authentic versions to download is to download it directly from the manufacturer such as Adobe, Symantec, Autodesk, Microsoft etc… Downloading from somewhere else is more than likely illegal.
The OEM versions are only to be sold with accompanying hardware. For example, Microsoft might allow a computer store to sell their computers with the Windows operating system either pre-installed on the computer or as a CD or DVD for the end user to install, but OEM software is never to be sold by itself but many people do it anyway.
There are plenty of places online to get authentic licensed software at cheap software prices but you just need to do a little homework to make sure it is authentic.
One easy way to find a definite source of illegal software is to do a whois search on the domain name of the website that is selling the software. If the name is registered to someone in a country other than the United States, and the software is a US based company such as Adobe, Microsoft, Corel, Intuit etc. then the software is more than likely not legitimate. And if there are any doubts, you can call the copyright owner of the software and ask them if the website you are looking at is indeed selling authentic software.