Interesting video, but it's not LPG, it's simply vapors from gasoline being forced through an airlock. It's not free since the initial liquid gasoline has to be obtained. It would be better to obtain a MSR XGK stove, which will burn gasoline, kerosene, diesel, aviation fuel, almost any petroleum product. I have one here somewhere, hopefully I'll stumble over it while we're packing for the big move.
I'd be hesitant to reproduce the experiment in the video, because of the flammability of gas. I went through the burning gas experiments when I was 12 or 13 years old. I'd be willing to watch someone else do it, as long as I was 20-30 feet away
