Yeah, OKC to PA should be less than that. Are they shipping it via air freight? I suppose that included crating the stuff.
I can understand if it was to me in Alaska, but just to PA? Maybe it's something about PA. I bought 5 tires from an outfit in PA and they wanted $3000 to ship them when I checked online. I called and asked "NO, REALLY, how much does it cost to ship a tire to Alaska?" and the response was $600 per tire. I told them I could fly there and bring them back as baggage for less. They were offering free shipping to the "Continental" US (really meaning Contiguous, since Alaska IS on the same continent.) So I had them shipped to a freight forwarder and paid $180 for them to bring them to me in Alaska.
BTW, shipping charges is one reason I drove to Kansas City and OKC to get parts for my truck project. It cost me more than paying shipping, but I got to enjoy the trip, too.