How much should a Gas mask/Respirator cost?

Pricing guidelines on how much you should spend on a gas mask or respirator. In this video, I take into consideration the prices of antique gas masks from WW1 and WW2, as well as more modern military surplus masks. For the preppers side of things, I take into consideration the price of newer models of military surplus masks using 40mm filters and the cost of both disposable and reusable industrial respirators. An important point to consider is the cost of new filters for these masks, 40mm NBC/CBRN filters,