A false sense of security is a very dangerous thing. There are much better products out there there that would provide the proper protection for about 80 dollars.

The biggest killer in fires is the inhalation of CO, Hydrogen Cyanide,etc.. a few breaths of some of the other components generated in a fire will kill you quickly. Spending 80 dollars for the proper equipment is a great investment, especially if you work in a building that requires you to walk several hundred feet before getting out. I would also recommend a good flashlight like the Streamlight Survivor LED (alkaline model) etc.. and those two items can really make a difference.