Where Is The Best Place To Hold A General Party In PA?

I have a party business and am looking for a place to have a once-a-month open house kind of deal where people who do not have the room in their house can have one of my parties to get the 10% discount on items, 40% off one item, etc. And I have no idea how to find something like that. Is there a place where party halls are advertised? I do not want to spend a lot of money. If anyone knows of places in/near Harrisburg that are cheap to rent, please let me know. Thanks.