JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" id="pack11049" class="DoPricing" />
<input type="checkbox" id="pack21199" class="DoPricing" />
<input type="checkbox" id="pack31199" class="DoPricing" />
<input type="checkbox" id="pack41299" class="DoPricing" />
<input type="checkbox" id="pack61499" class="DoPricing" />

<select id="HowMany" class="DoPricing">
    <option value="0">0</option>
    <option value="1">1</option>
    <option value="2">2</option>
    <option value="3">3</option>
    <option value="4">4</option>
</select>

<div id="TotalPrice"></div>

JavaScript

var OptionPricing = {
    
    'pack11049': 1049,
    'pack21199': 1199,
    'pack31199': 1199,
    'pack41299': 1299,
    'pack61499': 1499
};

var AccompPricing = {
    0: 0,
    1: 129,
    2: 258,
    3: 1057,
    4: 1856    
};

function checkOptions() {
    
    var Price = 0;
        
    for (Packs in OptionPricing) {
         
        if ($('#' + Packs).is(':checked')) {           
            Price += OptionPricing[Packs];
        }
    }
    
    return Price;
}

function checkAccomp() {
    
    var Accomp = parseInt($('#HowMany').val(), 10);
    
    return AccompPricing[Accomp];
}

function updateTotal() {
    
    var ThePrice = checkOptions() + checkAccomp();
    
    $('#TotalPrice').text(ThePrice);
}

$(function () { $('.DoPricing').click(updateTotal); });