JSFiddle - React, Tailwind, and code Playground

HTML

<div id="priceList">
<select class="participant" name="price1" style="width: 100%" onchange="sumValues('#priceList', '#totalPrice')">
    <option value="0" price="0"> 0€ </option>
    <option value="1" price="10.62" selected="selected"> 10.62€ </option>
</select>
<select class="participant" name="price2" style="width: 100%" onchange="sumValues('#priceList', '#totalPrice')">
    <option value="0" price="0"> 0€ </option>
    <option value="1" price="13" selected="selected"> 13€ </option>
</select>
</div>
<strong id="totalPrice"></strong>

JavaScript

sumValues('#priceList', '#totalPrice');
function sumValues(list,total){
    var allListElements = $( "select" );
    
    var sum = 0;
    $( list ).find( allListElements ).each(function() {
        console.log(Number($('option:selected', this).attr('price')))
        sum += Number($('option:selected', this).attr('price'));
    });
    $(total).empty();
    $(total).append(sum+' €');

}