I know it's not the best of deals, but if you are spending some money at CDWow anyway, then this is an added bonus. REMEMBER - CDWow do have some great prices on DVD box sets!
Instructions: Simply spend £29 or more in the online store, and they will send you a £3 voucher to be used off your next purchase. As they have some very decent prices in their bargain basement for old favourites, this could mean a CD for next to nothing! When the £5 vouchers were on recently, I got Wayne's World for free and had a good chuckle while watching it... sscchhhhwwwing!