Yes, downtown is mostly pay parking- there is some street meter parking, but your best bet will be one of the many all-day manned lots. You'll see a lot of them and signs downtown in the historic district, don't worry. Expect to pay $6-$9 for the day. There are also a few garages, depending where downtown you are but the small manned lots are your best bet- crime can be a problem here and location is an issue.
There is a ton of stuff to do in the area- most will cost you some money, but not everything.
Charlestowne Landing, its a historical site but also has miles of great walking in pretty gardens and forests, and has a zoo type place- local animals in natural habitat.
The Friends of Charles Towne Landing
Magnolia Plantation- the plantation itself is cool but what we love is the swamp walk, we always see'gators!
Magnolia Plantation and Gardens
Downtown the historic district is a must!! Lots of neat shops and restaurants, brick and cobblestone streets, huge old houses and buildings.... something we like to do a lot because its FREE is cemetery walk down there. There are hundreds of years old cemeteries w/some really cool stones and peaceful settings. You can also ride a horse carriage ride through town, that can get expensive but its one of the best ways to hear the local history and lore. Theres an old slave market on market street where you can sometimes get a good deal, but be prepared a lot of stuff is marked up downtown and city taxes SUCK.
Make sure you walk over to the famous Battery and gazebo.
Take a boat ride to Ft Sumter, where the civil war began
Fort Sumter National Monument - Fort Sumter National Monument (U.S. National Park Service) you can catchy one from downtown by the aquarium, or over by Patriots pt.
Patriots Pt is cool too, they have an old air craftcarrier, submarine and an old CG cutter you get to explore.
Patriots Point Naval & Maritime Museum - Charleston Harbor, SC
Downtown, the Old Provost and Dungeon can be a fun tour-
The Old Exchange and Provost Dungeon
There is a childrens museum downtown for the little one, IMO its not very good, but for a very small child can be a nice distraction.
There is also an Aquarium downtown- again, I'm not very impressed by it.Its pretty small compared to many we've been to.
Its Riverdogs baseball season. Here is their game schedule-
riverdogs.com: Home
One super fun and free thing is to walk the bridge... there is an awesome walk and bike lane completely gated off so its safe, all the way across-
Official SCDOT Website for the Cooper River Bridge (Arthur Ravenel, Jr. Bridge)
There is a waterfront park area downtown by the Vendue Inn- you'll see it.
And everyone loves to just walk and gawk at the mansions.
As far as food, a lot of tourists like Hymans Seafood- my fav is over the bridge, The Crab HOuse. Awesome food!!!
Charleston Crab House
For something fun for the kids, good mixed drinks, and yummy food- its a chain but still nice, Bubba Gump Shrimp Co has a place on Market St. For lunch, The Hominy Grill is good. Both places can be googled.
Good luck, we're finishing a 2 yr job here and have enjoyed it other than the traffic and crime.