I have been quoted £250 all in (drugs, call out, castration) provided there are no complications.
Cheaper for the bigger ones as they can be gelded standing. Shets are too small to geld standing (or so my vet says) and require "knocking out"for the deed.
It cost me £250 to have mine done nearly 2 years ago, pretty sure they had him down as he was a midget back then and the vet couldnt see even when he was kneeling on the floor!!