You have misunderstood the thresholds for the higher gift voucher amounts are reached by total number of purchasers i.e. do not all need to be your friends. Plus there is a separate element whoever gets the most referrals gets £100.
You need to get 120 friends to buy the deal to get just the £25 gift card. Ridiculous.
Response from Leanne at Buyapowa. Thanks for getting in touch. I believe they are valid for a year, in line with Debenhams' standard gift card T&Cs (I have left the office now as have the Debenhams team so can't check until tomorrow morning). But I can confirm that they are valid against anything, not just the AW trend pieces, and that there is no minimum spend. :) Regards, Leanne
A gift-voucher's a gift-voucher. Can't see how this would be restricted to anything. Seems a great way to get £30 for £15. I'm in!
Looks a little suspicious - I can't see anywhere how long you have to spend the gift voucher once the promotion ends and whether it is limited just to the Autumn/Winter collection.