Solution:
In the plugin, there is option Maximum Value to allow you to deactivate the product fee if the product price exceeds a certain amount . Please read https://docs.woocommerce.com/document/payment-gateway-based-fees/
After check this plugin. there is no option for minimum amount. but you can make fee 0 if total amount is 0. open the file woocommerce-additional-fees\classes\class-wc-add-fees.php.in calculate_gateway_fee_product add the code.
if($check_total==0){
return $check_total;
}
before return $fees_calc; in line no 2122 . if any query you can comment.