Being you already have the gun I would say that IDPA is going to be the most cost friendly competition to get into. All you need is 1 gun, 1 holster, 1 double magazine pouch and 3 magazines. Your cover garment can be a simple button up shirt or the shirt you wear to the match.
NRA Life Member, NRA Range Safety Officer, NRA Certified Pistol Instructor, IDPA Safety Officer, USPSA NROI Range Officer,
As you are, I once was, As I am, You will be.