As others have said, HMV really didn't help themselves with regards to their pricing. I was looking for all the seasons of a tv programme & my local HMV were selling all 6 seasons on DVD separately at a cost of £20 per season, £120 total. I eventually bought from Play for £36.99 the complete boxed set of all 6 seasons. An £83 saving is not to be sniffed at, even though I understand that they have overheads that online stores don't have.
I think they've only been able to carry on trading for so long with their mostly horrendous prices because going in to HMV & being able to buy a cd or DVD immediately gives instant gratification rather than having to order online & wait 3-5 days. Especially on older products.