This code use to deduct amount automatically from paypal buyers account. It is something like advance payment mode. If user agree with automatically deduction when he / she paying through paypal then amount will deduct according to billing period.

//step1. include paypal.class.php file (find attached file)

  include_once('paypal.class.php');
  $objPaypal  =   new MyPayPal();

  $PayPalMode         = 'sandbox'; // sandbox or live
    $PayPalApiUsername         = 'xxxxxxxxx'; //PayPal API Username
    $PayPalApiPassword         = 'xxxxxxxxx'; //Paypal API password
    $PayPalApiSignature     = 'xxxxxxxx'; //Paypal API Signature
    $PayPalCurrencyCode     = 'USD'; //Paypal Currency Code
    $PayPalReturnURL         = 'http://localhost/payapl_requirring/createRecurringPaymentsProfile.php'; //Point to process.php page
    $PayPalCancelURL         = 'http://localhost/payapl_requirring/cancel_url.php'; //Cancel URL if user clicks cancel

//step 2.

    $padata =     '&METHOD=SetExpressCheckout'.
                '&RETURNURL='.urlencode($PayPalReturnURL).
                '&CANCELURL='.urlencode($PayPalCancelURL).
                '&PAYMENTREQUEST_0_PAYMENTACTION='.urlencode("Authorization").
                '&L_PAYMENTREQUEST_0_ITEMCATEGORY0=Digital'.
                '&L_PAYMENTREQUEST_0_NAME0=xyz'.
                '&L_PAYMENTREQUEST_0_NUMBER0=132456'.
        '&L_PAYMENTREQUEST_0_DESC0=xyz'.
                '&L_PAYMENTREQUEST_0_AMT0=12'.
        '&L_PAYMENTREQUEST_0_QTY0=1'.
                '&PAYMENTREQUEST_0_AMT=12'.
                '&L_BILLINGTYPE0=RecurringPayments'.
                '&L_BILLINGAGREEMENTDESCRIPTION0=12.00 per month';
                //'&L_PAYMENTTYPE0 = Any';

    $request    =   $objPaypal->PPHttpPost('SetExpressCheckout', $padata, $PayPalApiUsername, $PayPalApiPassword, $PayPalApiSignature, $PayPalMode);

//step 3. redirect to checkout page.

    $request    =   explode('&',$request);
    $request    =   explode('=',$request[0]);
    $token      =   $request[1];

    $paypalurl ='https://www'.$paypalmode.'.paypal.com/cgi-bin/webscr?cmd=_express-checkout&token='.$token.'';

    header('Location: '.$paypalurl);

//step4. create file createRecurringPaymentsProfile.php and enter below code

include_once('paypal.class.php');

    $objPaypal  =   new MyPayPal();

    $PayPalMode         = 'sandbox'; // sandbox or live
    $PayPalApiUsername         = 'xxxxxxxxx'; //PayPal API Username
    $PayPalApiPassword         = 'xxxxxxxxx'; //Paypal API password
    $PayPalApiSignature     = 'xxxxxxxx'; //Paypal API Signature
    $PayPalCurrencyCode     = 'USD'; //Paypal Currency Code

    $paypalmode     =   ($PayPalMode=='sandbox') ? '.sandbox' : '';

    $padata         =   '&Method=GetExpressCheckoutDetails&TOKEN='.$_GET['token'];

    $request    =   $objPaypal->PPHttpPost('GetExpressCheckoutDetails', $padata, $PayPalApiUsername, $PayPalApiPassword, $PayPalApiSignature, $PayPalMode);

    $request    =   explode('&', $request);
        $arrData    =   array();
    foreach($request as $payData){
        $payData                    =   explode('=',$payData);
        $arrData[$payData[0]]       =   $payData[1];      
    }


    if(!empty($arrData)){
    $padata =     '&TOKEN='.urlencode($_GET['token']).
        '&PAYERID='.urlencode($_GET['PayerID']).
        '&PAYMENTREQUEST_0_PAYMENTACTION='.urlencode("SALE").
                '&BUTTONSOURCE  =  AngellFreeInc_USBSwiper_EC_US'.

        //set item info here, otherwise we won't see product details later  
                '&L_PAYMENTREQUEST_0_NAME0=xyz'.
                                '&L_PAYMENTREQUEST_0_NUMBER0=132456'.
                                '&L_PAYMENTREQUEST_0_DESC0=asfasdfsf'.
                                '&L_PAYMENTREQUEST_0_AMT0=12'.
                                '&L_PAYMENTREQUEST_0_QTY0=1'.               

                                '&PAYMENTREQUEST_0_ITEMAMT=12'.
                                '&PAYMENTREQUEST_0_TAXAMT=0'.
                                '&PAYMENTREQUEST_0_SHIPPINGAMT=0'.
                                '&PAYMENTREQUEST_0_HANDLINGAMT=0'.
                                '&PAYMENTREQUEST_0_SHIPDISCAMT=0'.
                                '&PAYMENTREQUEST_0_INSURANCEAMT=0'.
                                '&PAYMENTREQUEST_0_AMT=12'.
                                '&PAYMENTREQUEST_0_CURRENCYCODE='.urlencode($PayPalCurrencyCode);


    $request    =   $objPaypal->PPHttpPost('DoExpressCheckoutPayment', $padata, $PayPalApiUsername, $PayPalApiPassword, $PayPalApiSignature, $PayPalMode);

    $request    =   explode('&', $request);
        $arrData1    =   array();
    foreach($request as $payData){
        $payData                    =   explode('=',$payData);
        $arrData1[$payData[0]]       =   $payData[1];      
    }

        if(!empty($arrData1)){
                $date = (date('d')+1);

                $padata =  '&TOKEN='.urlencode($_GET['token']).'&PROFILESTARTDATE='.urlencode( date("Y-m-").$date .'T'.date("H:i:s"). 'Z' ).'&DESC=12.00 per month&BILLINGPERIOD=Month&BILLINGFREQUENCY=12&AMT=12.00&CURRENCYCODE=USD&L_PAYMENTREQUEST_0_ITEMCATEGORY0=Digital&L_PAYMENTREQUEST_0_NAME0=xyz&L_PAYMENTREQUEST_0_DESC0=asfasdfsf&L_PAYMENTREQUEST_0_AMT0=12.00&L_PAYMENTREQUEST_0_QTY0=1&EMAIL=harryalm54@gmail.com';

                $request    =   $objPaypal->PPHttpPost('CreateRecurringPaymentsProfile', $padata, $PayPalApiUsername, $PayPalApiPassword, $PayPalApiSignature, $PayPalMode);
                $request    =   explode('&', $request);
                $arrData1   =   array();
                foreach($request as $payData){
                    $payData                    =   explode('=',$payData);
                    $arrData1[$payData[0]]       =   urldecode($payData[1]);      
                }

                print_r($arrData1);


        }

        //step last
    }