JSFiddle - React, Tailwind, and code Playground

by Viktor L

HTML

<form action="" id="our-form">
  <div>
    <label for="item-1">Доставка</label>
    <input type="checkbox" name="item-1" id="item-1" value="100"> 
  </div>
  <div>
    <label for="item-2">Установка</label>
    <input type="checkbox" name="item-2" id="item-2" value="150"> 
  </div>
  <div>
    <label for="item-3">Настройка</label>
    <input type="checkbox" name="item-3" id="item-3" value="200"> 
  </div>
  <div>
    <label for="item-4">Обучение</label>
    <input type="checkbox" name="item-4" id="item-4" value="250">
  </div>
  <div>
    <label for="item-5">Обслуживание</label>
    <input type="checkbox" name="item-5" id="item-5" value="300"> 
  </div>
</form>
<div>
  Стоимость <span id="price">2000</span>руб.
</div>

JavaScript

var total = 2000;
function CalculateTotal(){
    $("input:checkbox").each(function(){
        if($(this).is(":checked")){
            total += parseFloat($(this).val());
        }
    });
    $("#price").html(total);
}

$("input:checkbox").change(function(){
    total = 2000;
    CalculateTotal();
}).trigger("change");