I have a 50 movie pack - 12 disks, double sided dual layered DVD's - that I bought on ebay a while ago. Voyage to the prehistoric planet is one of them I think, they are ALL on par with each other.
One of them, can't remember which right now, is SO cheap and nasty that they didn't have money for the evil alien Overlord's costume .. or his headquarters .... so they dressed him a gorilla suit but put a cheapo "space helmet" on the top and called him a robot. I kid you not! His lair is a "narrow" vertical workstation type affair in the mouth of a dry and dusty cave. World domination here we come!
Don't get me wrong, I knew what I was buying when I got these, as nasty as they are I really enjoy some of these old crappy B&W sci fi horrors.
I could tell you about another movie in this pack with the monster that has ping pong balls for eyes, but I think you get the picture.