CaroHell is one seriously over-priced park; as a result, discount tickets are fairly easy to find:
Specially marked Coke cans and Sundrop cans (a local soft drink -- try it!) have $10 off the ticket price.
Bojangles gives away coupons.
Harris Teeter sells tickets in its stores for a discount.
Without having looked at the prices this year, a season pass is usually less than the cost of two days' tickets.
Some of these coupons may be good for weekdays only.
If you go mid-week, I doubt you'll want to return for a second day; this park can easily be "done" in one day if there are no crowds.
Other hints about this park:
It's not easy to find the entrance to rides -- you'll be able to see the ride, but you can walk all around and fail to find the entrance! -- be sure to pick up a park map when you enter.
Carowinds' food is not very good, and it's expensive. The best-bets inside the park are Chickfillet and Subway (though they don't have the whole menu available). When we go, we always leave at mid-day and eat outside the park; there's plenty of good food just outside the gate.
Gas is cheaper in SC than in the surrounding states; you'll find two good gas stations right outside the park entrance.
The water park is INSIDE the main park and doesn't require a separate ticket.
The water park is very nice, but the lifeguards are insanely evil to little kids.