T&K Outdoors has the absolute lowest prices I have found on brand new firearms, anywhere in SC. He is pretty much a one-man outfit in a trailer off John Dodd Road in Inman, so he has very little overhead...but passes the savings on to his customers (prices are consistantly 15% lower than other dealers in the area). If you need a new gun I would definately buy it from T&K. The only problem is that he only deals in new firearms, and does not take trade-ins.
Allen Arms in Greenville is way overpriced, as is their range.
Fast Cash Pawn shop on 221 in Chesnee is a step up from your typical pawn shop. The guys there are pretty friendly, even if they can't always tell you a lot about what's in the case. Prices are pretty good too, as is their selection of used firearms.
The Sportsman in Rock Hill has average pricing, but a large rental case of firearms and an indoor range. They also give 30 days free range time with any gun purchase, which I like because it encourages new gun owners to become familiar with what they just purchased. Most of the staff is friendly and helpful. The range is cheaper than most ($10 per hour), and they allow you to bring your own ammo, and keep your own brass, as any range ought to. No rapid fire or rifle calibers though.
Teague's Pawn on Cherry Road in Rock Hill is a pawn shop, but it's clean, well-lighted, and has a friendly staff. Their prices on new guns are around MSRP (which is rare for a pawn shop IME), and used guns are usually priced fairly.
In Spartanburg, Dunbar & Zimmerli Outfitters has guns priced a bit higher than others, but they have assisted me in returning two guns to the factory at no expense, and have given me good prices on guns I bought from them and later traded in on more expensive guns. Camp Croft Pawn has been hit-or-miss for me; some of the stuff in there is a good deal but other items are overpriced. He includes tax on all guns though, so if you can make it there on tax free weekend and ask nicely, you'll get a pretty good cash discount.
Academy Sports often has guns at wholesale prices (or below), but you can expect the same extra paperwork hassle and uninformed staff as with most large chain stores.
Avoid the Southern Sportsman and Personal Security Supplies, both in Boiling Springs. Also avoid David's Pawn and Rock Hill Pawn in Rock Hill. David's has a friendly staff, but outrageous prices. RH Pawn is run by a bunch of *******s and idiots, and has outrageous prices. Last time I went to RH Pawn (and it will be the last time), they had a beat-up police trade in Glock 22 in the case for $625. Gen 2, 2 mags, dead night sights, 80% or less finish, and $100 more than a NIB Gen 3 G22 would cost.