Total sum of checkbox values

I have a simple checkbox code, 2 checkboxes per group.

    <div class='product-addon'>
        <p>Interfejsy</p>
        <label>
            <input id='option0' type='checkbox' name='Interfejsy' value='150.00'>
            Moduł rozszerzenia 1: 2x RS232 <span class='addon-price'>150,00</span>
        </label>
        <label>
            <input id='option1' type='checkbox' name='Interfejsy' value='370.67'>
            Moduł rozszerzenia 2: WiFi <span class='addon-price'>370,67</span>
        </label>
    </div>
    <div class='product-addon'>
        <p>BAZA</p>
        <label>
            <input id='option0' type='checkbox' name='BAZA' value='60.00'>
            Rozszerzenie bazy PLU o 2000 kodów  <span class='addon-price'>60,00</span>
        </label>
        <label>
            <input id='option1' type='checkbox' name='BAZA' value='80.00'>
            Rozszerzenie bazy PLU o 4000 kodów  <span class='addon-price'>80,00</span>
        </label>
    </div>

My question is: How i can get total sum of price (checkbox.val()) when user click checkbox? For example user click checkbox in first group with value=150.00, and click checkbox in second group with value=80.00? Total sum should be 230.00 Important: user can select only one checkbox in group.

I have that js code:

    var totalSum = 0;
    $("input:checkbox").on('click', function() {
      var $box = $(this);

      if ($box.is(":checked")) {
        var group = "input:checkbox[name='" + $box.attr("name") + "']";
        var addonPrice = parseFloat($box.val());
        $(group).prop("checked", false);
        $box.prop("checked", true);
      } else {
        $box.prop("checked", false);
      }

      totalSum += addonPrice;
      console.log(totalSum);
    });

but the variable totalSum is always getting higher, when i click any addon. For example i click checkbox in group 1 with value=150, next click checkbox in group 2 with value=60, totalSum = 210 it's good, but when i click again some checkbox it's adding next value.

I just wan't something like this: 1) User click checkbox in group 1 with value=150 2) User click checkbox in group 2 with value=60 3) totalSum is 210 4) User click checkbox in group 2 with value=80 5) totalSum is 230, not 290

Thanks for any suggestions