I've got Continentals on mine 235's all round, it had them from new at the time, and I've just stuck with them, I'm more than happy with them, ride is good with no intrusive road noise, and the grip in both wet and dry is very good.
Prices, well I paid about £235 for the rears, and that included fitting and balancing, but I could have got the tyre cheaper over the net (& they included vouchers for fitting etc) but I did not have a credit card they accepted!
Theoretically, the rears last approx 12k and the fronts up to 18k, but I have exceeded that, depends on your driving. Then again my other cars used to suffer with worn outer/inner edges etc, but I have the pressures checked every weekend, and check the tyres every couple of weeks for wear etc to prevent that from happening.
AG