The core Wolfram Engine is free for non-production use. While it lacks the standard "Notebook" interface, you can pair it with free editors like Jupyter or Visual Studio Code to get a similar experience.
If your goal is to use Mathematica's powerful computational engine without a high upfront cost, consider these official channels: Mathematica 5.2 For Students Free Download
You can use the Wolfram Cloud for free. This provides a web-based notebook interface where you can write and execute code with some limitations on computation time and storage. The core Wolfram Engine is free for non-production use
Most major universities provide free Mathematica licenses for students. You can check if your school is part of this program via the Wolfram License Search . Mathematica 5.2 For Students Free Download