This is your last chance to grab this route at this great price because the Southwest sale ends tonight. This fare which is part of the distance based sale is available Monday through Thursday and Saturdays starting in early November through February 13, 2019. Other than blackout dates around peak holiday times this deal is wide open and easy to find.
As with all Southwest fares you'll need to book directly on the Southwest website, and don't forget to pack all you need as two bags fly free.
For example, I found seats departing ATL on Thursday, December 6 and returning from PIT on Monday, December 10, 2018.
Need a room in Steel town? Here's what's available for the mentioned dates on Hotelwatchdog.