I just recently bought some sheet film - 4x5 HP5+ in the 100 sheet box, here in the US, from B&H. The price did seem quite a bit higher than my mental image of what the film costs (over $1.20 per sheet), I am not sure if there has been a recent price increase, or if I just haven't been paying attention over the past few years. Either way, I do not begrudge Ilford charging a fair price for their film so long as it supports a business model which will allow them to continue offering the film for as long as I want to shoot it.
FWIW, I also bought some Velvia - that costs $3.50 per sheet, and the chemicals to process it cost me another $2.00 per sheet so it is over $5.00 each time I trip the shutter to get a poorly exposed transparancy . Both the chemicals and the film seemed to be a lot less expensive just a few years ago.