I wanted to download some movies on my sons new Samsung tablet.I have already bought some from the play store and are quite expensive.?

Whenever you find a commercial video ($$) on a website that does NOT also offer the same video there for free, means that you now know the video is NOT available elsewhere for free:

IF you choose to try, and that specific video is found on other websites for free, and you knowingly attempt to download it anyway, you are guilty of Software Piracy. The Courts do not buy your claim that you didn't know it was illegal to steal a copy.

These video files are likely Copyrighted and Copy-Protected, and the rightful owners will prosecute anyone caught illegally PIRATING them. Besides, all parents should try to teach their kids to do "what is right" by setting a good example.

I don't understand entirely what you're asking.

You have already been able to download some movies from the play store, has anything changed to stop this working any more?

Of course, you can't possibly be asking about how to download movies you haven't paid for since obviously that would be illegal.

Try looking around at archive.org .

I wanted to find either cheaper or free movies

And what is your question?

Use torrent.. using utorrent is better..
Just type movie name torrent download.. select one.. and click the magnet link..