Things on this page are fragmentary and immature notes/thoughts of the author. Please read with your own judgement!
The YouTube video Open-Source License Explained in 5 minutes has very nice summary of different types of opensource licenses.
You can use a copyleft licensed source code in your commercial software under the condition to share your source code.
You can use a weak copyleft licensed source code in your commercial software under the condition to share the modified source code.
You can use a permissive licensed source code without sharing anything.