Получить значения инпута цены и количества

var sum = 0;
var kolvo = 0;
var multiplier = 0;
$('.minus').click(function () {
  var $input = $(this).parent().find('.kolvo');
  var count = parseInt($input.val()) - 1;
  count = count < 0 ? 0 : count;
  $input.val(count);
  $input.change();
  return false;
});
$('.plus').click(function () {
  var $input = $(this).parent().find('.kolvo');
  $input.val(parseInt($input.val()) + 1);
  $input.change();
  return false;
});
$('.oct-input-td').on("change", function() {
  var sign = $('.price').val();
  sign = parseInt(sign);
  sum += sign;
  
  updateTotal();
});
$('.oct-input-td').on("change", function() {
  var sign = $('.kolvo').val();
  sign = parseInt(sign);
  kolvo += sign;
  
  updateTotal();
});
$(".form-group").on("change", ".checkbox", function() {
  var sign = $(this).prop("checked") ? 1 : -1;
  multiplier += sign * $(this).val();
  
  updateTotal();
});
function updateTotal() {
  $(".sum").text( Math.round( ( sum * kolvo ) * ( 100 + multiplier ) / 100 ) );
}

.row {
    display: flex;
    flex-wrap: wrap;
}
.col-lg-6 {
  position: relative;
    width: 100%;
    flex: 0 0 50%;
    max-width: 50%;
    }
    .table-responsive {
    margin-bottom: 1rem;
    border-radius: 0.25rem;
    font-size: 1rem;
    background-color: #fff;
    border: 1px solid #b5c3c6;
}
tbody {
    display: table-row-group;
    vertical-align: middle;
    border-color: inherit;
}
tr {
    display: table-row;
    vertical-align: inherit;
    border-color: inherit;
}
td {
    
    vertical-align: inherit;
}

<script type="text/javascript" src="https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js"></script>
<div class="row" id="price">
  <div class="col-lg-6">
    <div class="table-responsive">
      <label class="control-label">Простые танки</label>
      <table class="table">
        <thead>
          <tr>
            <td class="oct-col-option-name">Значение</td>
            <td class="oct-col-option-price">Цена</td>
            <td class="oct-col-option-quantity">Кол-во</td>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td class="text-left td_name">5 уровень (ТТ, СТ, ЛТ, ПТ)</td>
            <td class="text-left td_price" style="text-align: center;">450р.</td>
            <td class="text-left oct-input-td" style="display: flex;">
              <input type="checkbox" class="price" value="450" style="display: none;">
              <button class="oct-button minus" type="button">
                <i class="fa fa-minus"></i>-
              </button>
              <input type="number" class="kolvo" value="0">
              <button class="oct-button plus" type="button">
                <i class="fa fa-plus"></i>+
              </button>
            </td>
          </tr>
        </tbody>
      </table>
    </div>
  </div>
  <div class="col-lg-6">
    <div class="table-responsive">
      <label class="control-label">Сложные танки</label>
      <table class="table">
        <thead>
          <tr>
            <td class="oct-col-option-name">Значение</td>
            <td class="oct-col-option-price">Цена</td>
            <td class="oct-col-option-quantity">Кол-во</td>
          </tr>
        </thead>
        <tbody>
          <tr>
            <td class="text-left td_name">5 уровень (ТТ, СТ, ЛТ, ПТ)</td>
            <td class="text-left td_price" style="text-align: center;">450р.</td>
            <td class="text-left oct-input-td" style="display: flex;">
              <input type="checkbox" class="price" value="450" style="display: none;">
              <button class="oct-button minus" type="button">
                <i class="fa fa-minus"></i>-
              </button>
              <input type="number" class="kolvo" value="0">
              <button class="oct-button plus" type="button">
                <i class="fa fa-plus"></i>+
              </button>
            </td>
          </tr>
        </tbody>
      </table>
    </div>
  </div>
</div>
<div class="row">
  <div class="col-lg-7 form-group required">
    <label class="control-label">Настройки заказа</label>
      <div class="row">
        <div class="col-lg-4">
          <label class="label">
            <input value="25" class="checkbox" type="checkbox">
            <span> Срочный заказ</span><span class="price red"> +25%</span>
          </label>
          <label class="label">
            <input value="10" class="checkbox" type="checkbox">
            <span> Аккаунт на EU</span><span class="price red"> +10%</span>
          </label>
        </div>
        <div class="col-lg-6">
          <label class="label">
            <input value="5" class="checkbox" type="checkbox">
            <span> Прислать скриншоты и реплеи боев</span><span class="price red"> +5%</span>
          </label>
          <label class="label">
            <input value="25" class="checkbox" type="checkbox">
            <span> Аккаунт свободен только ночью</span> <span class="price red"> +25%</span>
          </label>
        </div>
    </div>
    <div class="col-lg-9">
      <label class="label">
        <input value="40" class="checkbox" type="checkbox">
        <span> Сделать ВСЕ задачи на ОТЛИЧНО</span><span class="price red"> +40%</span>
      </label>
    </div>
  </div>
  <div class="form-group">
    <div>Стоимость:</div>
    <div><span class="sum">0</span> руб.</div>
  </div>
</div>