JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
<input type="checkbox">
<input type="checkbox" checked>
<input type="checkbox">
<div>$<span id="price">0.00</span></div>

JavaScript

$(':checkbox').change( function(){
    var sum = $(':checked').length
    var price_total = sum*1.99;
    $('#price').html(price_total.toFixed(2));
})