If you want to modify the plugin then you can do so of course it is GPL.
Find function qpp_process_form
in legacy/quick-paypal-payments.php
and find
<input type=”hidden” name=”currency_code” value=”‘.$currency[$id].'”>’;
and add no_shipping
e.g.
<input type=”hidden” name=”currency_code” value=”‘.$currency[$id].'”>
<input type=”hidden” name=”no_shipping” value=”1″>’;
Of course this is just guidance, I haven’t tested it and changes you make are as always at your own risk. ( as it the use of the plugin anyway )
Of course any changes you make would be overwritten by releases, so it will be up to you to ensure you have a mechanism to stop that – I would recommend completely cloning the plugin changing the plugin name etc.
If you like, I could actually add this as an option within the core plugin, but that will take me time to code / test / release and for my time I do need to charge costs.