The Pro version of My Scans without any ads and watermark on the generated PDF files normally costs $5.99 is free with App of the day today on Play store. You need to download it through App of the day app to unlock the pro version features. To get the pro version for free just download the app through the App of the day app and open it.
It has 4 start rating on the play store. It may not be as good as the Cam Scanner but it's free for lifetime and you don't need to worry about the ads or watermark on your PDF anymore.
I will try this.