I feel like my Hewes lappy is a great all-around boat for the Charleston area, and you can find them in your budget pretty easily. It gets skinny enough for nearly all of my flood tide flats (very infrequently I may get out and wade), I am a little limited at times in skinny low tide creeks, but I almost exclusively fly fish and it has served me very well for the last 4 years or so. Plus, I can run across the harbor or fish the jetties no problem. I would feel comfortable cruising the outside for kings or tarpon, and setting up on the inlets to fish bait for big reds or tarpon is easy too.
If you exclusively fly fish and prioritize getting skinny over a little open-water capability, maybe look at a Mitzi or Salt Marsh/Ankona. You'll get beat up in the harbor or even when the breeze picks up in some of the rivers, but that's the tradeoff for super-easy poling and skinny creeks. I can run 40mph through slop in the Hewes, but I've got to put a little more work in when it's time to pole the boat around.