White Zombie is considered to be the first zombie movie. You may also be interested to know (or not) that it inspired the name for the band White Zombie.
It’s in the public domain, so it can be purchased cheaply or viewed for free online here. But no matter how you watch it, don’t expect excellent sound or picture quality. Partly because no studio owns the copyright, it hasn’t been remastered or restored like some other classics. Though, personally, I watched it on a cheapie DVD and it didn’t bother me.

As for the actual movie, I thought it was surprisingly very enjoyable. Lots of atmosphere adds a certain creepiness throughout. Not to mention Bela Lugosi, who is very good as the zombies’ cruel master. Those spooky eyes are legendary…