It's illegal to fish that many commercial pots, or to sell your catch, without a commercial license ($25 resident, $300 nonresident) and pot license numbers ($25 resident for up to 50 pots, $125 nonresident).
The law is less clear (and the published regs even less so) than in some states, with regard to the equipment that a recreational crabber can use. It says you can only have two crab traps or pots, but "trap" is defined in the actual law as "an enclosed device used for taking fish, constructed to facilitate entry but prohibit or restrict exit of fish and is also called 'pot'." That doesn't seem to cover traps that only close when you pull them, so you could have a dozen or more of those. You might need pot licenses for those, you might not. I think that if you use them for "commercial purposes," they become "commercial equipment," and have to be licensed.
Of course, you should probably call DNR to see how they view the law.
http://saltwaterfishing.sc.gov/pdf/mr_act_2000.pdf[ Anonymized URL Blocked ]
http://www.dnr.sc.gov/admin/divphone.html