I love the convenience of flying from ACY, due to where I live ... I love a 15 minute ride to a small airport with short lines and short walks.
And I also love flying to WDW.
So I put up with Spirit's fees. And yes, the fee is in each direction. So if the fee for a first bag is $15 and you are flying round-trip with one suitcase, you will pay $30 in baggage fees for your trip.