PayPal API with PHP - single payment, then recurring payment with different amount - php

Question

I am using the following code to send a payment request to PayPal's API (the $field array in the $paypal class is used to build a POST request). This code works fine.
$paypal = new paypal_class;
$paypal->add_field('business', $store_email);
$paypal->add_field('return', $script_location.'?action=success&order_id='.$order_id);
$paypal->add_field('cancel_return', $script_location.'?action=cancel');
$paypal->add_field('notify_url', $script_location.'?action=ipn');
$paypal->add_field('item_name_1', strip_tags(str_replace("'","",$_POST["description"])));
$paypal->add_field('amount_1', $amount);
$paypal->add_field('item_number_1', $item_id);
$paypal->add_field('quantity_1', '1');
$paypal->add_field('custom', $_SERVER['REMOTE_ADDR']);
$paypal->add_field('upload', 1);
$paypal->add_field('cmd', '_cart');
$paypal->add_field('txn_type', 'cart');
$paypal->add_field('num_cart_items', 1);
$paypal->add_field('payment_gross', $amount);
$paypal->add_field('currency_code', strip_tags(str_replace("'","",$_POST["currency"])));
$paypal->submit_paypal_post(); // submit the fields to paypal
Now, let's say the $amount I'm sending is $199. This amount will be charged correctly using the code above. Now I want to charge $29 per year in addition to the initial $199. Can I modify the code above (sending some extra fields presumably) to accomplish this?
I've been looking through the docs and I've seen some options for recurring billing but can't find one for exactly what I'm looking for - which is an initial payment of Amount X and then recurring payments of Amount Y.

Answer 1

You can offer a trial period of any amount including 0. The Trial period is the initial payment and after the trial period is over then you can setup the actual subscription amount, and start the billing on a specific date.
Here is the documentation for Express Checkout:
Express Checkout Recurring with Trial Period
&TRIALBILLINGPERIOD=Month #Period of time in one trial period
&TRIALBILLINGFREQUENCY=1 #Frequency of charges, if any, during the trial period
&TRIALTOTALBILLINGCYCLES=1 #Length of trial period
&TRIALAMT=0 #Payment amount (can be 0) during the trial period
&CURRENCYCODE=USD #The currency, e.g. US dollars
Here is the documentation for direct Recurring Payments
Trial Period for Direct Recurring Payments

Answer 2

It looks like you're working with Payments Standard. Can you confirm that?
If so, the answer pp_MSI_Jenn gave isn't going to apply. That said, I would recommend you switch to Express Checkout if you're comfortable with PHP class (which apparently you are.) This class library will make Express Checkout very simple for you.
You'll be working with the following API's.
SetExpressCheckout
GetExpressCheckoutDetails
CreateRecurringPaymentsProfile
Since you mentioned that you want to charge a one-time amount of $199 and then $29/year after that, you actually don't need to mess with a trial period. Instead, you'll just use the INITAMT parameter in the CRPP request to process the $199. Then you'll use the regular AMT, BILLINGPERIOD, BILLINGFREQUENCY, etc. to setup the $29/year, but you'll set the PROFILESTARTDATE to be 1 year from the current date. That way the first $29 payment won't happen for 1 year, but you'll get the $199 right away when the profile is created.
If you'd rather stick with Payments Standard, then you actually could utilize the trial period as a work-around the way pp_MSI_Jenn mentioned doing with Express Checkout. You would set the trial period for 1 year and use the $199 amount for that period, and then set the regular period to $29/year.
For more details on that look at the Sandard Varaibles list, specifically the recurring payments section.