In an ideal world £3.50...but I understand there are costs involved so
£6-10 for an album depending on number of tracks.
My problem is I'm running out of room to store CD's I buy and I only put them on my I-pod and file them away anyway. So its more practical sometimes to just download rather than have a physical CD. If I go to a gig and like the artist I'm more likely to buy the CD especially if I can get it signed or the little booklet in it is of interest.