As Jordy says, a lot more info is needed (but also tell us how flexible you are over dates and times) before we can give a useful response.
I can only imagine you don't have a railcard, and that you aren't travelling back in the same day, and that you aren't travelling before 0900 M-F (a lot of assumptions there - please correct me...) in which case the SVR fare is £73.70*...
With such a wide range of routes available, it is no easy task to calculate the best fare, and indeed it does depend on whether you have a preference for a particular route and also what day you are travelling (engineering works, etc) and what time, but I am confident we can drastically reduce that price to a much lower level.
Over to you...!
(* NFM95, out of date now)