As my rear tyres are getting towards the wear bars I have been looking around and prices varied by around £50 on the Michelins I wish to get, I'm staying with them as they're a good tyre with long wear rates and excellent grip/feel also the fronts have about half their usable tread left. For reference my rear tyres are 265/35/19N2.
Of the suppliers I've checked, OPC were dearest at £267/tyre, Event Tyres about £30/tyre less and Black Circles being the cheapest at £223, so if you want Goodyears it will be a full set and probably best to try Black Circles but shop around.