You might want to take a look at this thread, link below. Kenneth came up with some rather simple jQuery (see below) that adds/subtracts and gives a final total, rather than a whole bunch of rather convoluted getBy elements: It may be applicable for your usage, I don't know.
http://forums.adobe.com/thread/1168391?tstart=120
Example as provided by Kenneth:
<!DOCTYPE html>
<html>
<head>
<title>Test</title>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.7.1/jquery.min.js" type="text/javascript"></script>
<script>
var BASE_PRICE = 625;
var total;
function doTotal() {
total = BASE_PRICE;
$("input[type='checkbox']").each(function(index, element) {
if(element.checked) total += +element.value;
});
$("#total")[0].value = "$" + total;
}
</script>
</head>
<body>
<form>
<input name="double-pedestal-legs" type="checkbox" id="double-pedestal-legs" value="550" onclick="doTotal()"/>
<label for="double-pedestal-legs">Double Pedestal Legs</label>
<p>+$550</p>
<input name="full-base-sheet" type="checkbox" id="full-base-sheet" value="75" onclick="doTotal()"/>
<label for="full base sheet">Full Base Sheet</label>
<p>+$75</p>
<input name="raised-rail" type="checkbox" id="raised-rail" value="125" onclick="doTotal()"/>
<label for="raised-rail">3/4" Raised Rail</label>
<p>+$125</p>
<label for="total">YOUR DREAM TABLE IS ONLY:</label>
<input name="total" type="text" id="total" readonly value="$625" />
</form>
</body>
</html>
