Wings
100 atlantic beach causeway, +1-252-240-2628; and 200 w fort macon road, +1-252-240-5363, (http://www.wingsbeachwear.com/). the largest beach shop on the island, with beach apparel, souvenirs and accessories.
Bert's Surf Shop
304 w fort macon road, +1-252-726-1730, (http://www.bertsurfshop.com/). a local chain north carolina plus myrtle beach offering beachwear, surfing gear, skateboards and accessories.
Kites Unlimited
Atlantic station shopping center, +1-252-247-7011, (http://www.kitesunlimited...). if you want a kite to fly on the beach, this should be your first stop; they also sell banners, flags and windsocks, as well as games. the shop sponsors a kite-flying group in the area on weekends, and a kite-flying festival in late october.
Freeman's Discount Bait and Tackle
108 atlantic beach causeway, +1-225-726-2607 or +1-888-827-fish 3474, (http://www.freemanstackle.com/). open daily. the oldest bait and tackle shop on the island, with over 1200 feet of retail space. offers rods and reels, inshore and offshore tackle, bait fresh or frozen, live or artificial and in-house rod and reel repair.
Beach shops are abundant, if you're desperately in need of a surfboard / beach towel / flip-flops / sunglasses / lucite dolphin sculpture. Two of the more prominent ones are listed below, but you'll see plenty of others in the nearby vicinity:
Otherwise, you mostly have the traditional beach gifts: seashells, things carved out of seashells, things made from seashells, things made from driftwood, salt-water taffy and nautical-themed items. A lot of it is tacky and cheap; some of it is really nice quality.
A couple of specialty shops that might come in handy for your seaside vacation needs: