You don't need expensive software to learn math. The open-source community has created incredibly powerful and free tools.

1. GeoGebra: The king of open-source math software. It's a stunningly powerful suite for algebra, geometry, and calculus.

2. Maxima: A full-featured Computer Algebra System (CAS) that can handle symbolic manipulation, calculus, and more. A free alternative to Mathematica.

3. SageMath: A massive, comprehensive system that brings together dozens of open-source math projects into one interface.

4. LibreOffice Calc: Don't underestimate the power of a spreadsheet. It's a fantastic tool for exploring functions, tables, and data.

5. Jupyter Notebook: The standard for data scientists. It lets you combine live code, equations, visualizations, and narrative text.

Open-source means these tools are free forever, with passionate communities constantly improving them.

They give you access to the same kind of power used by professional mathematicians and scientists.

Exploring these tools will take your understanding to a whole new level.

Embrace the power of open-source and supercharge your learning.