Went in to Debenhams today to pick some stuff up in the sale, and lo and behold, they are currently running a special offer for free £15 iTunes vouchers.
EDIT: The gift cards must be purchased in store. The offer IS national but some stores are being slack and not offering the promotion when they should be. Try complaining to head office!
You CAN use the gift cards to buy things online. But the cards must initially be bought in store to get the free iTunes gift card.
The exact special offer is:
Buy a £100 gift card, and receive a £15 iTunes voucher for free. Offer ends Saturday I think. Or sunday, can't remember. Either way, it only started today.
But the obvious answer is, if you're buying something for £100+ just buy a gift voucher then use that to pay for it.
Split my shopping into two and got two of them, the sales assistant couldn't believe more people hadn't thought of it!
This is at least in store (I was in Meadowhell), may be online as well, haven't checked in all honesty!