Depends where you are in the country really and what kind of shavings you are after. I have used Arley Moss Supplies for many years who are based North West but can deliver (at cost) all around the country, I am in Peterborough in East of England and used to cost about £50 for the delivery. They do a really wide range of bedding too, all of it shown on their website and also a shipping cost calculator.
If you can specify which area you are looking for, someone else might have a more local supplier they can recommend.