Seems amazingly variable to me! I'm in Hampshire and just paid £45 for big round bales of haylage (lovely stuff it is too thank heavens), and £40 for big round hays, also lovely stuff.
Seems gut wrenchingly expensive at the time of handing over the £'s but probably worth it as one feeds my four for two weeks.
Seems to me the further North or West you go the cheaper it gets but of course I may be wrong