I myself had been given on different occasions Amazon vouchers and very happy about it. They have always been used for book purchases.
Another alternative would be to give away an Amazon - Gift Basket, who arrived also very good. The gift basket is filled with original Belgian specialties, smoked products, sweets and wine, and which is available in different designs and price ranges.
At my request the recipient of such a basket, the response was absolutely positive. The edibles contained therein were described as very delicious and tasty.