MPEG 2 is lossy compression, When you put a single movie on a DVD, you are leaving behind a huge amount of data. Putting 3 or 4 movies on a DVD?
Though you may get it free or very cheap, in terms of quality it is an absolute no no. Recently on a visit to Dubai, I went into a shady by lane and picked up 3 or 4 DVDs of what is called 'Classic BMA Movies'. The BMA is styled like BMW. Each DVD has some 16 movies. There is one for James Bond, one for Jean-Claude Van Damme, Jet Li, Harrison Ford, etc.
I tried a few, and they are terrible. I have three DVD players that are certified DIVX capable. None of them play beyond the 4th or 5th movie. And when they play, the output is terrible.
I am using these DVDs to to sample the movies like a Trailer. If I like the movies, I will run out and buy the original.