商品の値段とNSNumberFormatter

SKProductの価格の加工などで使う。

    NSNumberFormatter *formatter = [[NSNumberFormatter alloc] init];
    formatter.formatterBehavior = NSNumberFormatterBehavior10_4;
    formatter.numberStyle = NSNumberFormatterCurrencyStyle;
    formatter.locale = locale;
    NSString *string = [formatter stringFromNumber:price];