I have been searching for a while trying to find a place that could make a copy of my key. A friend told me he had one made from a non MB blank at ace hardware but could not remember what kind of car the blank was from. I searched through what they had and found that one of the Mazda key blanks was very similar. I had them go ahead and make a copy, and it worked.
It sometimes takes just a little wiggling, but I can put up with that since it only cost me $ 3.00 instead of $ 80.00 to $ 100.00 that the locksmiths were wanting.
The part number for the Mazda key at ACE Hardware is MZ19p.
Thought I would share this info with the rest of you.