How to subtract values of radio buttons

Question

How can I calculate a set of radio buttons using JavaScript? It works as of now with adding up the total. but I would like it to Subtract the $150.00 off.

this is what I been working on now I get $Nan

<p>Baby Plan<br />
    [radio BPSUBPT id:BPSUBPT class:radio-vertical "Baby Plan $300.00 3 Sessions" "Baby Plan $500.00 4 Sessions"] </p>

<p>Did you have a Newborn session With ADP? <br />
[radio BPSUPQ id:BPSUPQ class:radio-vertical "Yes$ -150 off" "No"]


<p>Baby Plan Totals: <br />
Baby Plan Price: [text BPSUBPP 28/28 id:BPSUBPP]
Discount Amount: [text BPSUDA 8/8 id:BPSUDA]

Total Price: <span id="total"></span



<script>
        $(document).ready(function() {
      var inputs = $('input[name="BPSUBPT"], input[name="BPSUPQ"]');
            $(inputs).click(function() {
                var total = 0;
                $(inputs).filter(':checked').each(function() {
                    var value = ($(this).val()).match(/\$([0-9]*)/)[1];
                    total = (parseInt(total) - parseInt(value)) 
                })
               $('#total').html('$' + total);
            });
            $('input[name="BPSUBPT"]').click(function() {
                $(this).blur();
                $('#BPSUBPP').val($(this).val());
            })
            $('input[name="BPSUPQ"]').click(function() {
                $(this).blur();
                $('#BPSUDA').val($(this).val());
       });
        });
    </script>

Answer 1

You should probably just ADD the totals:

<p>Baby Plan<br />
[radio BPSUBPT id:BPSUBPT class:radio-vertical "Baby Plan $300.00 3 Sessions" "Baby Plan $500.00 4 Sessions"] </p>

<p>Did you have a Newborn session With ADP? <br />
[radio BPSUPQ id:BPSUPQ class:radio-vertical "Yes $-150 off" "No"]
<!-- beware here because I changed "Yes$ -150" to "$-150" -->

<p>Baby Plan Totals: <br />
Baby Plan Price: [text BPSUBPP 28/28 id:BPSUBPP]
Discount Amount: [text BPSUDA 8/8 id:BPSUDA]

Total Price: <span id="total"></span

jQuery

$(document).ready(function() {
    var inputs = $('input[name="BPSUBPT"], input[name="BPSUPQ"]');
    $(inputs).click(function() {
        var total = 0;
        $(inputs).filter(':checked').each(function() {
            // Now including the - sign
            var value = ($(this).val()).match(/\$(-?[0-9]*)/)[1];
            if (value) {
                // I'm now ADDing the total
                // total = total + parseInt(value);
                total += parseInt(value);
            }
        });
        $('#total').html('$' + total);
    });
    $('input[name="BPSUBPT"]').click(function() {
        $(this).blur();
        $('#BPSUBPP').val($(this).val());
    });
    $('input[name="BPSUPQ"]').click(function() {
        $(this).blur();
        $('#BPSUDA').val($(this).val());
    });
});

Answer 2

Don't use decrement/incrementation of total, count right total every time.

Add attribute cost to each valuable input(price or discount) and:
Try this:

$('input').click(function(){
   var total = 0;
   $('input').filter(':checked').each(function(){
      var cost = $(this).attr('cost');
      cost = cost ? parseFloat(cost) : 0;
      console.log(cost);
      total += cost;
   });
   $('#total').text('$'+Math.max(total, 0));
})

<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>

<input cost="300" type="radio" name="BPSUBPT" value="Baby Plan $300.00 3 Sessions"> Baby Plan $300.00 3 Sessions<br/>
<input cost="500" type="radio" name="BPSUBPT" value="Baby Plan $500.00 3 Sessions"> Baby Plan $500.00 3 Sessions<br/>

<input cost="-150" type="radio" name="BPSUPQ" value="Yes $150.00 off" />
Apply Discount?<br/>
<input cost="0" type="radio" name="BPSUPQ" value="No" />No<br/>

<div id="total">

Update:

Answer 3

I think whats happening is you're working with negative numbers.

When you do total = total - parseInt(value); you are subtracting the value as determined by the radio buttons from 0. (var total = 0;). So your total is actually a negative number.

You probably want to add there, and then make the value of the 150 discount -150, and add that to your total.