Which movie has the highest box office revenue to prodution cost?

Question

I would like the answer for actual cost and also for ratio if possible. My first thought was the Blair With Project but I have been told that is wrong. Was there a lower budget movie with an even bigger impact??

Answer 1

I really think it's The Blair Witch Project.
It had a budget of $35,000, and went on to make almost $250 million worldwide, in theaters.

Answer 2

It is either Terminator or Clerks