There exist also open source software, just as freeware it is free for personal, educational and commercial use. The only difference between freeware and open source is that complete source code of the latter can be freely downloaded and even modified by anybody. So that programmers can use that open source software, modify it and even distribute modified versions! What they can and cannot do is determined by a license open source software comes with. There exist plenty of them, some are more permissive, others are less. The most known open source licenses are GPL and BSD.
Notable examples of worldwide known open source software are numerous variants of GNU/Linux operating system (alternative to paid Windows), LibreOffice office suite (alternative to paid Microsoft Office), GIMP – GNU Image Manipulation Program (alternative to paid Adobe Photoshop), Java programming language and environment (currently the most demanded programming language in the world), MySQL, PostgreSQL database management systems (alternatives to paid Microsoft SQL Server, Oracle DBMS) etc.
Those programs are very often of way better quality than their paid competitors.