I am kinda partial to the 9x18 MAK. I own several guns chambered for that round, one of my favorites is the Polish P-64. It is a PPK look a liike, easily concealed, fairly accurate out to about 40 yards. As an occasional carry gun, it is loaded with Hornady 95gr JHP/XTP. They perform well on bowling pins, and should offer a fair amount of stopping power if needed.
As for reloading for the round, you can purchase bulk factory ammo for about 5 bucks a box when bought in lots of 100 or more. I don't think you can reload that cheap.