That is the question.
By the spare mags first. Then you have to get the gun.....My PT92, PT100, and 24/7 G2C all came with two mags. Truthfully, the only thing stopping me from getting a PT740 is the fact that the only ones I have seen only come with one mag. Why would anybody buy a pistol with only one mag these days? Especially when you consider how difficult it is to get additional mags.