JSFiddle - React, Tailwind, and code Playground

HTML

<div class="pricefield">// now all comes dynamically
    <label>first</label>
    <div class="" d-field>
        <select id="1">
            <option value="1">first</option>
            <option value="2">secound</option>//may be more options</select>
    </div>
    <label>secound</label>
    <div class="" d-field>
        <select id="id">
            <option value="4">first</option>
            <option value="5">secound</option>//may be more options</select>
    </div>// may be more select</div>

JavaScript

get_sum();
$('#1 select').change(function () {
    get_sum();
});
function get_sum() {
    var sum = 0;
    $('#2 select').each(function () {
        sum += parseInt($(this).find("option:selected").val());
    });
    alert(sum);
}