Originally Posted by
1kwannabe
Ticket frm GSO to PRG in Y is running 796.00
If I book to FRA it is 537.00 and LH frm FRA to PRG is 150.00
THank you in advance for the advice and hope someone could shed light on this

You would likely have been abe to get it all on one ticket for $687.00 (or maybe a bit less with taxes).
If you got UA to fare you thru to FRA on UA with the connection on the cheap LH code you find FRA-PRG, it would have priced properly.
You would have needed an agent (or a third-party booking engine) however, to do this.