Code was fine, you just overlooked to set priceWithoutTax with F2 => "All prices should be displayed to the second digit after the decimal point! The discount is applied only on the total price. Discount is only applicable to the final price!"

 Console.WriteLine($"Price without taxes: {priceWithoutTax}$");

change to :  

Console.WriteLine($"Price without taxes: {priceWithoutTax:F2}$");

Correct form:

                Console.WriteLine("Congratulations you've just bought a new computer!");
                Console.WriteLine($"Price without taxes: {priceWithoutTax:F2}$");
                Console.WriteLine($"Taxes: {sumTax:F2}$");
                Console.WriteLine("-----------");
                Console.WriteLine($"Total price: {totalPrice:F2}$");

Eто още едно подобно решение:

https://pastebin.com/suGKW8t3

Привет!

Малко късно, но по темата, бих искала да попитам - защо слагаме "client = Console.ReadLine();" в while цикъла, след if  и else?

Ще съм благодарна, ако някой ми обясни :)