Is the 42nd street Port Authority the same as 8th Avenue one?

Yes, P.A. is at West 42nd Street & 8th Avenue

Yea what's the rate./fare

Yes

Online the fare from NYC to Norristown PA was $ 20-25. But when i finally bought the tickets, i paid $ 37.50. The tickt lady at Greyhound said there was no service to Norristown! Eventually i got a tkt to Philadelphia and connecting bus to Norristown from Trailways! And the tkt says 'Greyhound Lines'. So i am confused...the fare discrepancy and the misinformation.

The correct address is 42nd and 8 th ave. So yea