I've just had my SC fitted and other half went a little mad and bought the contour girth, stirrup leathers and the double bridle to match the piping on the saddle too!
So have no idea how much the girth was - but I will say what a fabulous saddle - its made so much difference to my horse...... Highly recommended for anyone thinking of getting a new saddle for their horse!
My girth cost £95, I bought at the same time as the SC saddle so I don't know if you can get them without....I would imagine so. Have you tried looking at the website?