JSFiddle - React, Tailwind, and code Playground

HTML

<label id="subt0" data-original="8.90">8.90</label>

<input name="service1" type="checkbox" id="ser1" data-price="1" value="1" title="Service 1" />
<input name="service2" type="checkbox" id="ser2" data-price="5" value="1" title="Service 2" />

JavaScript

var subt_value = parseFloat($('#subt0').text());
var start_price = parseFloat($('#subt0').attr('data-original'));
        
        $("#ser1, #ser2").click(function(){
    
            var sub_total = 0
			var extra_fee = parseFloat($(this).attr('data-price')/1.12).toFixed(2);
			
			
            $(this).each(function(){
                if($(this).is(":checked")){
                    var sub_total = subt_value + parseFloat(extra_fee);
					$('#subt0').text(parseFloat(sub_total).toFixed(2));
                }else{
					$('#subt0').text(parseFloat(start_price).toFixed(2));
				}
            });
           
			
       });