What are the Cheapest Surplus Gas Masks?

I was asked if I could do a video regarding the cheapest surplus gas masks/respirators on the market, so that is exactly what this video is about. These masks are not necessarily good but they are cheap, as a general rule Warsaw PACT gas masks are cheaper than their NATO equivalents, so for the sake of diversifying the video, I have not made a video solely about PACT and Soviet respirators. Masks included in this video are: Soviet GP-5 Civilian gas mask Polish MC-1 gas mask French/Belgian M51 gas mask West