You can find a little vinyl at flea markets and about. Yard sells are another source around about.
Charleston is not exactly a huge audio market. There's a couple of audio stores but they generally don't stock much really high end. Read Brothers Stereo on King Street is the only real 2 channel dealer and the owner does like vinyl. Good place to deal with, nice people and he can order certain things. He just doesn't stock any because of low to no volume for it.
The audio warehouse is primarily home theater. They don't stock 2 channel.
I buy most of my equipment from Atlanta or other sources outside the state. I have never had a sale of used equipment here in the state. It all has gone out west or up north.
South Carolina is a really dead state for audio! Georgia and North Carolina offer much more.
It is one of the reasons why I worry about 2 channel and it fading away. It only seems to thrive in certain areas of the country.