I have a Samsung NX100 with the kit lens (20-50mm f/3.5-5.6, crop factor 1.54) and SEF15A flash (guide number 15, direct flash only), which as a whole cost me $300. I can't spend over that much on another accessory any time soon.
I'm an amateur looking for general-purpose stuff. Portability is hugely important, as I'm very petite with wrist issues. Most of my pics are either macro food photos or candids of people, usually street photography or on request for community events. Not a landscape person, so for most purposes my kit lens is perfect (if a little too slow for a lens without OIS).
These are the options I'm tossing up:
The SEF20A flash ( http://www.amazon.com/Samsung-ED-SEF20A-Camera-Flash-Nx/dp/B003GAS2EC ), $120 or so, not much brighter but can swivel vertically and thus do bounce flash. There's also a guide number 42 flash, but it's built more like a proper DSLR flash (and is thus bigger than my camera and a wee bit ridiculous).
The 50-200mm f/4-5.6 ( http://www.amazon.com/Samsung-50-200mm-Telephoto-Series-Cameras/dp/B004W81AM8 ), $250.
The 30mm f/2 ( http://www.amazon.com/Samsung-Pancake-Series-Digital-Cameras/dp/B006Z1HG3C ), $310 or so. There's also a 20mm f/2.8, but that seems slightly pointless to me.
For an amateur like me, what would you see as the one item most likely to allow me more flexibility and be most well used? Are there other things you would suggest?