Starting to look for a plate carrier or chest rig. New or used but not damaged too bad. Right now I have a few options in mind, but would like to see if I could keep the money here first.
If you ever plan on running soft armor (non-rifle protection), then you might want to consider something else.
Personally, I like to keep my soft armor and plates separate. Get yourself a plate carrier (and level III or IV plates) for 'tactical' and 'known-threat' scenarios and get a some concealable armor (IIIA) for less-likely scenarios.