Confused about Licenses

I’m starting to get more into GitHub. I want to download a particular package (clone) and take it in my own direction. It would be for a project that I could potentially sell individually, but I need the foundation as it’s already laid out.

Ignore the fact that I’m being overly ambitious and probably unrealistic and bear with me…

The license for this particular package has the usual “you can redistribute, sell, etc.” comment, but also states that anyone else who buys it has the same rights. What’s the protocol for this?

I’ve read that this is the reason why Open Source exists, but I don’t see what would stop someone from just finding the code online and copying it for free (I know that nothing is stopping someone from redistributing the product). Maybe what I’m really asking is…do I have to make the code available freely?

Another option would be to simply leave the package in place on GitHub and “install” it prior to making my own spin-off. Is this more aligned with what I’m trying to do?

Thanks in advance!

I think that this might be what you’re asking about (from the Open Source Initiative FAQ):

Can Open Source software be used for commercial purposes?

Absolutely. All Open Source software can be used for commercial purpose; the Open Source Definition guarantees this. You can even sell Open Source software.

However, note that commercial is not the same as proprietary. If you receive software under an Open Source license, you can always use that software for commercial purposes, but that doesn’t always mean you can place further restrictions on people who receive the software from you. In particular, copyleft-style Open Source licenses require that, in at least some cases, when you distribute the software, you must do so under the same license you received it under.

You may also be asking:

How do I make money if anybody can sell my code?

You can sell services based on the code (i.e., sell your time), sell warranties and other assurances, sell customization and maintenance work, license the trademark, etc. The only kind of profit strategy that is incompatible with Open Source is monopoly-based sales, also known as “royalties”. See this article for how to think about business strategies that make money from Open Source. Also, this 2015 survey of open source leaders (including many OSI Directors) provides several business models for Free and Open Source software.