Does it have to be Pittsburgh? I live here, but hardly ever fly out of here -- the price is generally higher than elsewhere. I'd try Cleveland or even Akron/Canton.
Also, use Expedia, Travelocity, etc., and when you find an okay price, go to the airline's site and check their price for that flight number -- sometimes they are the cheapest.
Also, be sure to add in the additional costs, like the charges for baggage.
HTH
Edie