sorry, i missed that this was for free tools.
change the shipping hidden element:
<input type="hidden" name="shipping" value="<?php echo $row_rs_users['fld_srPRICE']; ?>" />
to handling_cart:
<input type="hidden" name="handling_ cart" value="<?php echo $row_rs_users['fld_srPRICE']; ?>" />
see this page for more details on the variable reference for paypal add to cart buttons:
https://developer.paypal.com/webapps/developer/docs/classic/paypal-payments-standard/integration-guide/Appx_websitestandard_htmlvariables/