I strongly agree with the cautions raised by previous posts. Gasoline storage containers are not a place to cut costs.

I've seen massive expansion (in heat) where the containers were puffed out like a balloon. I've also seen massive contraction (in cold) where the sides were sucked in to an alarming degree.

Approved containers withstood this abuse without a problem. I would not trust anything else. There are enough hazards in life without creating an impromptu fuel-air explosive in the garage.