What about Southwest. They have good prices. But being spring break, may be booked. Go to their website and sign up for ding. They have "ding" specials and also internet specials. I have my PIT to MCO for 69.00 1 way. I started at 79.00 and keep modifying when a lower rate becomes available
Sorry just checked SW does not fly out of Atlanta or any airport near there. Airtran would be the next cheapest from what I've seen.