Foknik,
<script>
$(function() {
function calc() {
var $select = +$("select#select option:selected").data("service");
var $price_2 = $("input#check_2:checked").length ? +$("input#check_2:checked").data("price") : 0;
var $price_3 = $("input#check_3:checked").length ? +$("input#check_3:checked").data("price") : 0;
var $final_prise = $select + $price_2 + $price_3;
$("span#total").text($final_prise)
}
$("select#select, input#check_2, input#check_3").change(calc)
});
</script>