I am both a U.S citizen as well as a South African citizen. Next summer I plan to permanently move to South Africa with my boyfriend. I should be able to get into the country with just a one way ticket, right? And what about my boyfriend? (non S.A citizen) will he need a certain visa or just proof that he will be living with me? Since we are moving permanently we don't want to pay the extra money for a return trip, since we won't be returning. Would it be easier to get him in if we were married? I don't want any problems at the airport but I can't seem to find an answer anywhere online.
As a South African, all you need to enter South Africa is a South African passport (a South African ID book may even be enough).
Your boyfriend, however, naturally needs a visa (in fact, a temporary residence permit). There are multiple types of temporary residence permit, which can be seen at http://www.southafrica-newyork.net/homeaffairs/trp.htm. Most likely the General Work Permit is most appropriate. After five years of working in South Africa, he can apply for a permanent residence permit. If you were married, he could get a permanent residence permit directly.
He can apply for this at the South African Consulate responsible for your state (see http://www.southafrica-newyork.net/homeaffairs/jurisdiction.htm). They should be able to help him find which type of permit is suitable.
Enjoy South Africa!