/**
  * Build the Payment params
  */
 public function getCheapestMonthlyCost($cart = NULL, $cData)
 {
     if (!class_exists('CurrencyDisplay')) {
         require JPATH_VM_ADMINISTRATOR . DS . 'helpers' . DS . 'currencydisplay.php';
     }
     if (!class_exists('KlarnaAPI')) {
         require JPATH_VMKLARNAPLUGIN . DS . 'klarna' . DS . 'helpers' . DS . 'klarnaapi.php';
     }
     if (!isset($this->klarna) || !$this->klarna instanceof Klarna_virtuemart) {
         return NULL;
     }
     $display_fee = 0;
     $billTotalInCountryCurrency = 0;
     if (isset($cart->pricesUnformatted['billTotal'])) {
         $billTotalInCountryCurrency = KlarnaHandler::convertPrice($cart->pricesUnformatted['billTotal'], $cData['vendor_currency'], $cData['virtuemart_currency_id'], $cart->pricesCurrency);
     }
     if ($billTotalInCountryCurrency <= 0) {
         return NULL;
     }
     $aTypes = array(KlarnaPClass::ACCOUNT, KlarnaPClass::CAMPAIGN);
     $kCheckout = new KlarnaAPI($this->country, $this->lang, 'part', $billTotalInCountryCurrency, KlarnaFlags::CHECKOUT_PAGE, $this->klarna, $aTypes, JPATH_VMKLARNAPLUGIN);
     KlarnaHandler::getCheapestPclass($kCheckout, $cheapest, $minimum);
     vmdebug('getCheapestMonthlyCost', $cart->pricesUnformatted['billTotal'], $billTotalInCountryCurrency, $cheapest, $minimum);
     if ($billTotalInCountryCurrency < $minimum) {
         return NULL;
     }
     if (!class_exists('VirtueMartModelCurrency')) {
         require JPATH_VM_ADMINISTRATOR . DS . 'models' . DS . 'currency.php';
     }
     $sFee = $kCheckout->getPresentableValuta($cheapest);
     return $sFee;
 }