The best "antiques" places ( just one person's opinion, of course
) on the Grand Strand have closed, but there is a pretty big place in Murrell's Inlet that is a consignment venue with a good many booths. The exact name escapes me, as it changed about a year ago, but it is on BUS 17 heading south, barely south of the Inlet Mall... you need to turn right at the southernmost mall entrance road past Poppy's and the little shopping strip- and then take the immediate left into the parking lot of the shop. Its adjacent to the now-closed K&W cafeteria. Most of what I've seen there is overpriced, in my opinion, but that being said the variety of items is pretty good and especially if you are into old glass, art or wood you will probably find it interesting.
Also, Peggy's Antiques is a good place- its located in front of the Hudson's Flea Market, in the little log cabin. Great for scouting small items
As noted in the previous post, there are many consignment shops on BUS 17 from Murrell's Inlet all the way up into Myrtle Beach proper and there is a little flyer that maps everything in this area- you might check with your local haunt to see if they have a rack with similar pamphlets for your area. Just a note- it seems to me as I think about it that the shops on the northbound side of BUS 17 tend to be more in the "thrift shop" genre, where those on the southbound side are what most people think of as consignment stores.
Hope this helps-
Busy