Clearing caches, fully uninstalling apps and finding what filled the disk do not require a paid suite. These open-source or one-off tools each handle one part of the job.
A Mac app management utility that fully uninstalls applications and removes their leftovers, updates installed apps in bulk and shows what each one occupies on disk. It suits machines that have accumulated many apps.
A macOS maintenance utility that verifies the startup disk and system file structure, clears caches, removes applications and adjusts hidden preferences. It suits users who want to inspect or deep-clean the system by hand.
A tree-map disk analyser from the Omni Group that shows where space is going and lets you remove the largest files and folders directly. It suits tracking down what filled up a disk.
A Mac cleaning and maintenance app that clears caches and leftovers, removes applications, checks for security issues and tidies the system. It suits a regular routine of checking up and cleaning the machine.
A macOS performance monitor that surfaces CPU, memory, disk and network load from the menu bar and offers cleanup and optimisation suggestions. It suits users who want system load visible at all times.