JSFiddle - React, Tailwind, and code Playground

HTML

<span id="mybadge" class="badge badge-primary">$10</span>

<select id="myselect">
 <option value="$10">$10 Item</option>
 <option value="$20">$20 Item</option>
</select>

JavaScript

$('#myselect').change(function(){
    $('#mybadge').text($(this).val());
});