There are two stores. One is located in Mt Pleasant and the other one is located in my neighborhood. I find that Haddrell's has a great selection of products. Besides offering frozen bait, live bait, rods, reels, and tackle; they also offer guns, ammo, bows, arrows, accessories, etc.
My experience is that if it is not available they will order the item for you. This is what makes them great on customer service.
The store actually opens at 6 AM which is great for getting fresh bait in the morning. If you are interested in frozen bait they have a vending machine located outside so at least you get get some cut bait if they are closed when you arrive.
They also offer free seminars ranging on learning to tie flies, inshore fishing by species, fishing off shore, and even duck hunting has been offered in the past. During the seminars they will offer 10% off everything in the store.
Haddrell's has supplied me with most of my tackle and the guys there are a wealth of knowledge. They also host our local kayak club meetings throughout the year and support tournaments and charities around the Charleston area.