Carrefour in Spain have a really good loyalty card called Club Carrefour, which gives you cashback every 4 months in the form of savings vouchers.  These vocuhers have no minimum spend requirement.  For example, I recently got a voucher for around 5 euros and just used it to buy a couple of bottles of wine and that's it.  The main advantages of the Club Carrefour card are as follows:

• 1% cashback on all of your purchases of food and fresh produce, pharmacy items, toileteries, cleaning products and pet food in Carrefour stores and at www.carrefour.es
• 8% cashback when filling up at Carrefour petrol stations.
• 4% cashback at CEPSA service stations.

In addition to the cashback vouchers you receive every 4 months, we have also received several extra vouchers in the post from Carrefour over the last couple of years.  The most recent was a vocuher for €5 off a 40 euro spend and one for 25% off all soft drinks and beers.

You can ask for a Club Carrefour card at any till or at the customer services desk.  All you need to do is fill in a short form with your name and address and you should get your card straight away.