I solved this by simply using an array of objects. So for example, I am accepting registrations. So to get the total price I go about it like this:
var registrants = [];
registrants.push({ price: 30 });
registrants.push({ price: 10 });
registrants.push({ price: 20 });
var totalPrice = 0;
for(var x = 0; x < registrants.length; x++){
totalPrice += registrants[x]["price"];
}
and you would just update the price property of the corresponding registrant when appropriate.