I want to obtain Magnesium metal for my experiment. Powder would be best. Where can I get Magnesium metal free or at minimum cost?

Camping supplies, magnesium is sold as a "firestarter" aid in block form. Just grind off the amount you need. costs about $9 here in canada.

 

if you want it for free then put it in your pocket and make sure the cameras don't see you.

Not in powder, but a discarded electric water heater can have a lot left in its galvanic rod. Unscrew it and a Mg bar will come out.

A Volkswagen air cooled engine block + transmission housing from the sixties is 97% Mg.

Miguel

you know those old metal pencil sharpeners? they're made entirely from magnesium. you can tell because they're extremely light. The only parts which arent magnesium are the screw and the blade.

or just buy from united nuclear(not sure if this is spam but it is relevant), they sell it in the form of a granule powder, should be good form most reactions(thermite, grignard reagents, aqueous reduction, ect.)

I agree with hermanntrude, obtaining it from magnesium pencil sharpeners would probably be best. You can tell easily based upon the weight. Obtaining it through chemical means however, is rather complex, so the simplicity of this idea in contrast, makes it far better. If you require a strip, to use as a fuse, the metal is actually rather soft, and malleable. Certainly not as easy to cut as sodium, but certainly not such great an effort as steel. Best of luck,

 

,Theo