Showers are in the hostel ($20 for thru-hikers), the market is inside the building and there is a wide selection of hiking/camping supplies including food, sleeping gear, backpacks, nicknacks and anything you need to re-supply with.
This location is kind of famous. You read about it in the AT books and the owner has actually written a book about all the hikers he's met that happen through his shop. Neels Gap is not only a place to throw down for some sleep (they have a campground and a hostel), but it's a total resupply stop. We stayed at Neels Gap Camp because it fit our mileage plans and it was convenient for the night and it was a great place to catch up with folks we met on the trail and meet some new ones.
The hostel here is mainly for through hikers. They charge $20/night and that includes a shower and a bed. We stayed at the campground behind the building. There's nothing wrong with the campground, other than the fact that it's on such a slant (building camps on the sides of mountains and rocks does this…) that you are going to end up sleeping on top of your tent buddy if you don't aim your tent the right direction, and there are not many pads that allow the "right direction". You are truly best off in a hammock at this campground.
There are plenty of hammock trees, and it's kind of cool that the AT goes right past the tent pads so in the morning, you can watch the hikers filter out and head north on their journey. Old faces and new faces greet you as you sip your coffee and eat your oatmeal.
There is a fire ring, and since the fire ban ends on the other side of the highway (Neels sits on the highway), we were on the right side of the road to have a fire! A welcome addition to the chilly night air. There is a fire pit made of stone and everyone shares.
There were not many good spots to hang bear bags that were away from the tents, but we found one that sufficed. They do not have a bear box (and claim that bears don't really come to this campground, but can you really tell them not to?). They do, however, have mice, and one little bugger ate into my pack and buried a peanut inside. So best to put your pack in your tent, if possible. They're cute, but not that cute.
Portable pottys were located out front of the store, and there were about 5 that were fairly clean and maintained. There is a water faucet out front with drinkable water (yay!) that didn't need to be purified and picnic tables for cooking your food. A beautiful overlook while you ate was awesome too! There is a road/highway that passes by, so there is road noise, but not unbearable. Just kind of annoying if you are used to the sounds of the woods.
The store has anything you could possibly need for re-supply, which makes it totally awesome! Gear (packs, sleeping bags, shoes, socks, etc), cooking supplies (food, stoves, fuel), books, water bottles, you name it! They also accept resupply boxes that you have mailed to yourself and a system to hand them out that seems to work really well.
Overall, not a bad spot for camping. Everything you need in one spot.