Few days ago i found a store dealaboo.com where they are offering hp laptop deals, there are many laptops like pavilion, omni, g6, and many other machines are available in less price than others I like the website did I buy a machine from them.
this is the site address.
All USA prices for laptops are less than UK. Bear in mind, if you buy from US, you may have to pay Customs duties.
Try saveonlaptops, they seem to be about the cheapest for many laptops. Amazon also have good deals, but as most are through Amazon Marketplace, you need to check the individual sellers' reviews, to make sure they are reliable.
John Lewis do several HP models. You can check them out online, and then check if in stock at your local store. You can order on line, and collect from store. Their prices may not be the absolute cheapest, but the difference is usually small, plus you have the advantage that JL give a 2 year warranty on all their laptops (definately worth a couple of quid price difference), and their customer service is really good