Ok, it's actually listed as £24.99 on the website, but to get to the advertised price you need to do this;
a) go via the capital one link (-£1)
b) click on pigsback- cdwow link to get 10% cashback back there (-£2.40)
c) use a £2 voucher (-£2)
This should make it work out at £19.60. CDwow can occasionly cancel orders made usng combinations of discounts, but usually don't cancel your order.