For today only (Sunday) Disk Clean Pro is free in the Mac App Store. I had a play with it and it seems a functional and capable cleaner, so well worth a download.
EDIT: Some people are reporting that Sophos Antivirus is reporting this app is infected. This is a false positive, perhaps based on the somewhat generic and suspect sounding app title. If an app is in the Mac App Store then it’s been thoroughly checked over by Apple but just in case I ran BitDefender Virus Scanner and Malwarebytes Anti-Malware after installing and using this app. Nothing came back.