I got $71 each way PHL - Tampa. With fees that's right about what you're paying. There is an off chance you could save $5 - 10 per ticket, but not much more. Flying into Tampa is an alternative you could consider, but you're right in the ball park with the best fares from Philly.
Just wondering now....do mean $148 ONE WAY ?? If so my paragraph above does not stand. A $79 is what you should be working for. If you can wait for Southwest, you'll most certainly see bterr than $148 one way.
I too am wondering about the same. I watched spirit out of AC go from 95 bucks to 155 on the days i am going.. SWA is only booking up to oct and i am going back down dec 4..