Mobile operator

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String year = scanner.nextLine(),
                type = scanner.nextLine(),
                net = scanner.nextLine();
        int months = Integer.parseInt(scanner.nextLine());
        double price = 0;

        if (type.equals("Small")) {
            if (year.equals("one")) {
                price = 9.98;
            } else {
                price = 8.58;
            }
        } else if (type.equals("Middle")) {
            if (year.equals("one")) {
                price = 18.99;
            } else {
                price = 17.09;
            }
        } else if (type.equals("Large")) {
            if (year.equals("one")) {
                price = 25.98;
            } else {
                price = 23.59;
            }
        } else if (type.equals("ExtraLarge")) {
            if (year.equals("one")) {
                price = 35.99;
            } else {
                price = 31.79;
            }
        }

        if (net.equals("yes")) {
            if (price <= 10) {
                price += 5.50;
            } else if (price <= 30) {
                price += 4.35;
            } else {
                price += 3.85;
            }
        }

        double total = price * months;

        if (year.equals("two")) {
            total -= 3.75 * total / 100;
        }

        System.out.printf("%.2f lv.\n", total);
    }
}

ИЛИ:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String year = scanner.nextLine(),
                type = scanner.nextLine(),
                net = scanner.nextLine();
        int months = Integer.parseInt(scanner.nextLine());
        double price = 0;

        switch (type) {
            case "Small" -> {
                if (year.equals("one")) {
                    price = 9.98;
                } else {
                    price = 8.58;
                }
            }
            case "Middle" -> {
                if (year.equals("one")) {
                    price = 18.99;
                } else {
                    price = 17.09;
                }
            }
            case "Large" -> {
                if (year.equals("one")) {
                    price = 25.98;
                } else {
                    price = 23.59;
                }
            }
            case "ExtraLarge" -> {
                if (year.equals("one")) {
                    price = 35.99;
                } else {
                    price = 31.79;
                }
            }
        }

        if (net.equals("yes")) {
            if (price <= 10) {
                price += 5.50;
            } else if (price <= 30) {
                price += 4.35;
            } else {
                price += 3.85;
            }
        }

        double total = price * months;

        if (year.equals("two")) {
            total -= 3.75 * total / 100;
        }

        System.out.printf("%.2f lv.\n", total);
    }
}

Решеие с тернарен оператор:

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        String year = scanner.nextLine(),
                type = scanner.nextLine(),
                net = scanner.nextLine();
        int months = Integer.parseInt(scanner.nextLine());
        double price =
                (type.equals("Small") ? (year.equals("one") ? 9.98 : 8.58) :
                        type.equals("Middle") ? (year.equals("one") ? 18.99 : 17.09) :
                                type.equals("Large") ? (year.equals("one") ? 25.98 : 23.59) :
                                        type.equals("ExtraLarge") ? (year.equals("one") ? 35.99 : 31.79) : 0);

        double total = (price + (net.equals("yes") ? (price <= 10 ? 5.50 : price <= 30 ? 4.35 : 3.85) : 0)) * months;
        total -= year.equals("two") ? 3.75 * total / 100 : 0;

        System.out.printf("%.2f lv.\n", total);
    }
}