Originally Posted by Fitch

I would adivse caution here.

Firstly, not all the gift voucher amounts are on offer, only the following:

€50 for €40 (20% off)
€100 for €75 (25% off)
€200 for €140 (30% off)
€300 for €195 (35% off)

Secondly, the rules state (my rather free translation in blue):

• Vuelos operados por Iberia y otras compañías que sean en conexión (Iberia Express e Iberia regional Air Nostrum) siempre que en la ruta haya un vuelo operado por Iberia.
On flights operated by Iberia and other carriers having a connection (Iberia Express and Iberia Air Nostrum regional) provided that at least one flight in the routing is operated by Iberia
• Bono de un solo uso.
Single use voucher
• Bono válido hasta el 31 de Marzo de 2018.
Voucher valid until 31st March 2018
• Periodo de vuelo: Hasta el 31 de diciembre.
Fly until 31st December
• Periodo de vuelo no válido: del 1 de junio al 30 de septiembre.
Blackout period 1st June to 30th September
• Sólo compras desde España.
Only for purchase in Spain
• Sólo pago en Euros, y reserva en euros.
Pay in Euros only, and book in Euros
• No es válido para residentes y familia numerosa.
Not valid for non-citizens or large families (I think this means with 5 children or more !!!)
• No es combinable con Cash and Avios (Descuento con Avios)
Cannot be combined with Cash & Avios (Avios discount)
• No válido para vuelos de Puente Aéreo.
Cannot be used for flights on the Madrird-Barrcelona "air bridge" shuttle service


So unless you have a specific flight in mind, and a Spanish address, and a Spanish ID.... this one is probably not for you !