Question

1: How can a get the subtotal value based on each item value
2: When all calculation (each) is done how can I fire a function that will contain the subtotal value.

var subtotal = 0;

//Check each price
$.each(item, function() {

 var itemprice = $(this).val();
 var subtotal = subtotal + itemprice;

});

//When all items are added in the subtotal do something...

Answer 1

Assuming that item is a collection of prices…

var subtotal = 0;

//Check each price
$.each(item, function() {
    subtotal = subtotal + this;
});

//When all items are added in the subtotal do something...
alert(subtotal);

Remove the var before the second subtotal otherwise you are declaring a local variable rather than accessing the global one.

If the above code is already part of a function, then there is no need to call another function to do something with the subtotal (unless that code will be reused).