A running total - you could be selling anything whereby the client will see immediately how much the bill is (excluding tax or shipping).
In the qty part of the form, you'll need an id for each product for the script to identify. The format is PROD_PRICE, for example id="PROD_9.00" none of these values are passed to the cart, only the normal qty, product and price plus any others you may have inbuilt in your form.
I've placed in the form line, a script to ensure the minimum order value is $50.00, if this threshold isn't reached, the order isn't passed to Mal's.
If you do not need a visual running total on your page, simply change the line:
<input type="text" name="TOTAL" size="10" onFocus="this.form.elements.focus()">
<input type="hidden" name="TOTAL">