Multiple calcul in same function Jquery

I made a calcul for checkboxes and it works well.

HTML code :

$(document).ready(function() {
    function recalculate() {
    //prix de base du séjour    
        var sum = 940;
    //nb de participants au séjour          
        var nb_pax = parseInt(1+1);

        $(".chk_box:checkbox:checked").each(function() {
            sum += parseInt($(this).attr("price"))*nb_pax;
        });

        $(".budget").html(sum+' €');
    }

    $(".chk_box:checkbox").change(function() {
        recalculate();
    });
});

<script src="http://ift.tt/2a1Bldc"></script>
<div class="extra_libelle">
                                                        <label><input class="chk_box" type="checkbox" name="extras[]" price="142" value="1"> Transfers Ida/Volta  (aeroporto-hotel-aeroporto)</label>
                                                    </div>
                                                    <br/>
                                                    <div class="extra_prix">142 €</div>

 
                                                    <div class="extra_libelle">
                                                        <label><input class="chk_box" type="checkbox" name="extras[]" price="45" value="1"> Rafting</label>
                                                    </div>
                                                    <br/>
                                                    <div class="extra_prix">45 €</div>
       
      
                                                    <div class="extra_libelle">
                                                        <label><input type="radio" class="chk_box2" name="transports" value="0" price="0" checked="checked"> Eu já tenho a minha solução de transporte</label>
                                                    </div>
                                                    <br/>
                                                    <div class="extra_prix">0 €</div>


                                                   <div class="extra_libelle">
                                                        <label><input class="chk_box2" type="radio"  name="transports" price="396" value="6"> Voos Ida/Volta a partir de LISBOA (com transfers incluidos) </label>
                                                    </div>
                                                    <br/>
                                                    <div class="extra_prix">396 € </div>    


                                                    <div class="extra_libelle">
                                                        <label><input class="chk_box2" type="radio"  name="transports" price="596" value="6"> Voos Ida/Volta a partir de PORTO (com transfers incluidos) </label>
                                                    </div>
                                                    <br/>
                                                    <div class="extra_prix">596 € </div>
                                                    
                                                    <P>
                                                    <br/><br/><span>SUBTOTAL Extras : </span><span class="budget_extras">0 €</span>
                                                    <br/><br/><span>SUBTOTAL Transports : </span><span class="budget_extras">0 €</span>
                                                    <br/><br/><span>TOTAL : </span><span class="budget">940 €</span>
                                                    </p>

this is my code here : http://ift.tt/2lXg8Bm

But I want to make a bit more complex and the problem is :

• I don't know how to add the same calcul for radio button
• I don't know how to separate the subtotal to keep the subtotal of extras and subtotal of transport (to submit by POST method in input hidden later).

Any help appreciate.