I am flying down in aug returning the day after labor day. I am flying down on a Sat. which is typically higher. We have ding fares from SW for a party of 5 from philly for 499.50. I booked each leg seperately or over 1,000 RT. and when a ding fare came up I re booked that leg of the trip for the cheaper rate. It takes some time, checking ding every day and cx the first flight to get the second cheaper. If you book the exact date and time to a cheaper fare, sw will credit your credit card back. Otherwise if you change times or days for a cheaper fare you get a sw air credit to use within one year. I did get exact times on one of my flights so I have a refund back. For the other, I have a sw credit to use on a future flight.
You cann't go wrong with SW...