JSFiddle - React, Tailwind, and code Playground

HTML

<div class="mycont">
        <p id="excl" class="price excl">100 excl.</p>
        <p id="incl" class="price incl">200 excl.</p>
    </div>
    <button type="button">Click Me!</button>

CSS

.mycont > .price.incl {display: none}
.mycont.show_incl > .price.incl {display: block}
	.mycont.show_incl > .price.excl {display: none}

JavaScript

$('button').on('click', function(){
        $('.mycont').toggleClass('show_incl');
    });