Up towards Harrisburg right off route 83 might be a good bet. Even on Friday when there is business traffic, it's not too bad of a drive. You are only on route 30 for a few miles between 83 and Carlisle Ave to get to the Fairgrounds.
I routinely get a room for anywhere between mid $60's to maybe a high of around $80-$90 per night.
Prices are more reasonable if you don't mind an ~ 25 minute drive each way. Even with a car with bad gas mileage (I get around 20 highway), it's lot cheaper even if adding gas money to do a full cost comparison.
-Dave