There are plenty of property management companies. But ultimately, you could check all rentals available through the MLS online at any realtor's website (or at the master MLS website,
CharlestonTrident.com . Just select "rentals" as the property type before doing the search. If you need someone to show you listings in-person, then I'd check with an agent who specializes in showing rentals. I'll send you a DM of an agent I know who shows rentals, if you need.