I also sell stuff that have shipping charges associated with them. Every time one of my members wanted to make a donation, shipping charges would be added by PayPal. I would then have to go in and refund the shipping to the user. This was a big Pain in the A$$!!!
If this is happening to you, here is an easy fix:
In template
billspp_main, find this code:
Code:
<input type="hidden" name="item_name" value="$payfor" />
Right below that add this:
Code:
<input type="hidden" name="no_shipping" value="1">
A pretty simple fix for a really aggravating problem. Hope this helps someone.