JSFiddle - React, Tailwind, and code Playground

HTML

<label class="price">120</label>
<label class="price">250</label>
<label class="price">342</label>
<br/>
<label id="total"></label>

JavaScript

var sum = 0;
var prices = $("label.price");
for (var i = 0; i < prices.length; i++)
    sum += parseInt($(prices[i]).text());

$("#total").text(sum);