I spoke too soon!
Question -- currently with checkboxes there is the chance someone can select both and get charged for both priority and overnight shipping upgrades
I tried changing to radio buttons but to be a group they need to have the same name. When I changed name for both to upgrade the upgrade fee stopped being added
<?php
if (!session_id()) session_start();
if($_SERVER["REQUEST_METHOD"] == "POST") {
$_SESSION["upgrade"] = "".((isset($_POST["priority"]))?$_POST["priority"]:"") ."";
}
?>
<?php
if (!session_id()) session_start();
if($_SERVER["REQUEST_METHOD"] == "POST") {
$_SESSION["upgrade"] = "".((isset($_POST["overnight"]))?$_POST["overnight"]:"") ."";
}
?>
<input name="upgrade" type="radio" value="1" id="priority" />
USPS Priority : +$2.00<br />
<input name="upgrade" type="radio" value="1" id="overnight" />
USPS Overnight : +$7.50