JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/jquery-maskmoney/3.0.2/jquery.maskMoney.min.js"></script>
<div class="multi-field-wrapper">
  <div class="multi-fields">
    <div class="multi-field linha">
      <input id="quantidade" class="quantidade" type="number" name="quantidade[]" value="1">
      <input id="demo[1]" type="text" class="custo" name="custo[]">
      <button type="button" class="remove-field btn btn-danger">
        Excluir
      </button>
      <br>
    </div>
  </div>
</div>
<button type="button" class="add-field btn btn-primary m-l-20">
  Adicionar Campos
</button>
<div class="title">Total do Atendimento</div>
<span class="amount" count-to-currency="1123.99" value="0" duration="2">
  R$ <span id="valor">0,00</span>
</span>

JavaScript

$('.multi-field-wrapper').each(function() {
	//var max_fields      = 10; //maximum input boxes allowed
	var wrapper         = $('.multi-fields', this); //Fields wrapper
	var add_button      = $(".add-field"); //Add button ID

	$(add_button).click(function(e){ //on add input button click
		e.preventDefault();

		$('.multi-field:first-child', wrapper).clone(true).appendTo(wrapper).find('input').val('').focus();

			//re-init mask money to apply new added input 
			initMaskMoney();
		});
		
    $('.multi-field .remove-field', wrapper).click(function() {
			if ($('.multi-field', wrapper).length > 1){
				$(this).parent('.multi-field').remove();
        somarValores();
			}
		});
	});
	initMaskMoney();

	function initMaskMoney() {
		$('input[id^="demo"]').maskMoney({thousands:'', decimal:','}); 
	}
	$('.custo,.quantidade').on('change', function() {
		somarValores();
	});

	function somarValores() {
		var amount_sum = 0;
		//calculate total worth of money
		$('.linha').each(function(){;
    	var custo = $(this).find(".custo").val();
			var custoConvertido = parseFloat(custo.replace(",", "."));
			var quantidade = $(this).find(".quantidade").val();
			var total = custoConvertido * quantidade

			if (total > 0){
				amount_sum += parseFloat(total);
				sum = amount_sum.toFixed(2).toString().replace(/\./g, ',');
				console.log(amount_sum);
				console.log(sum);
			}else{
				sum = "0,00";
			}
		});
		$('#valor').html(sum);
	}