Sound Recorder was downloaded and installed by over 1M users and the latest stable release was on Aug 16, 2016. Ads are a part of this application. The app is often downloaded by Samsung and Sony users.
It's free of charge to download the .apk setup package of Sound Recorder and you can have a look at users' reviews on Droid Informer. This application installation package requires 3 MB of free space to work fine on Android 4.0 and higher.
Based on the users’ feedback, the obvious advantage of the app is a simple interface, although some people say that this application has such a disadvantage as spam ads.