First, you will need to learn how to do some programming and design. There are a lot of free tools out there to use in building software.
Some of the tools stay free after you start making money and others will charge you when you become profitable. That may seem like a good thing, but with a few exceptions, people get excited about a free software idea and then suddenly realize that if they spend time on that project, then they are not making money. So eventually the “community” will support the software and then die down. Sometimes companies offer free software, like Microsoft, but put restriction on the software. For instance the Express versions usually only support the current version of the .NET Framework.
Another approach is for software companies to provide the software for no cost, but expect you to pay when you make a profit. You might wonder how they will find out and charge you, but the process is easy:
So free software to be successful needs you to participate in the “Community”, or at sometime you need to pay for the software. It’s pretty simple. So if you are using free software make sure you understand the license.
If you are a student at a school in a STEM program you can get Windows 8 for “no cost” through the Dreamspark Premium program at your school!
If you have a “DBA” (Doing Business as), you can sign up for the 3 year BizSpark program, which is a very economical deal, but falls into the type of free software that you pay for when you are profitable.
Build Windows 8 Apps.
More on that later.
Talking about vendor who provide free software, I think "Winternals" (before being bought by Microsoft, did a good job.
The free brand "Sysinternals" provides many free neat tools that's popular among the system admin's communities, which in turn provide goodwill to their company.
IMO, it doesn't harm for companies to release "free" version of software of the same type, as long as they can address different marketing segment. The free version can be a just enough one that contains most of the things user needed, the "priced" version contains other beefy features.
Note that the "free" version shouldn't be a version that withholds important or even essential feature, or it would become a negative form of advertisement