To Remove PayPal, you realy just need to Remove the PayPal Express Checkout button on the checkout page.
Power store has support for UPS, Fed Ex and USPS already, to allow customers to chose which of these providers to use, add the following select list on the checkout page:
<select name="shipping_Provider" id="select">
<option value="1">UPS</option>
<option value="2">FedEx</option>
<option value="3">USPS</option>
</select>
Then add this code in on the confirm page around line 50:
<?php
if(isset($_POST['shipping_Provider']) && $_POST['shipping_Provider'] != "") {
$WAGLOBAL_Shipping = $_POST['shipping_Provider'];
}
?>
make sure it is just after the following:
<?php
require_once("WA_eCart/PP_ECO_Scripts/PP_ECO_PHP.php");
?>