Choose the best word to complete the gap: The price of the catalogue is ... against your first order.

The word that best completes the sentence is refundable.

Explanation: The sentence implies a discount or a return policy related to the first order. 'Refundable' fits this context, suggesting that if you place your first order, the price of the catalog might be refunded or there's a special refund offer.

Ответ: refundable