how much would it cost to have the car put into the assembly and get a locksmith to make a key for it? there is a car for sale but there are no keys for it (they are lost so he says) and so was wondering how much that would cost to make a new one without a backup?

not an extreme amount of money I'm sure... call triple A or some key store in your town and check on pricing... we don't really specialize on keys here

any idea of an actual number or an estimate?

that all could depend on if you could get the key code, and go to mazda and have one made!