Boots tends to be a bit pricey, but Jessops is a good bet. Also depends alot on the quality of the film you want. Branded film like Kodak is always much more expensive than unbranded film. Remember that the speed of the film also affects the price; so ISO100 film will be much cheaper (and better quality) than ISO400 but not so good in poor light conditions. Your small photo processing shops tend to do deals on multipacks of film.
My local Moss Pharmacy has 3 for �3 at the moment. I'm not into photography, but that seems quite a good deal to me - however it is the old "while stocks last" type offer.
I tend to buy here: http://www.mx2.co.uk/acatalog/MX2_co_uk_Camera_Foo d_56.html
it's best to know what type of film you're after first and worth baring in mind that some of their stock is close to expiry date though I haven't had any which is under 6 months to go and never had a single problem with it.
My father sends his film away to be processed at Trueprint (I think) for every film he has processed they send him two free films, he has not paid for 35mm film in years. Anybody know a better offer than that?
Depends what you're using the film for Phantaxus... in my opinion you get poor quality film and not so great processing from Truprint... remember there's no such thing as a free lunch!