Most responses will give you information free of charge.
If a fee is charged, it is likely to be small. Authorities are allowed to charge in certain circumstances but, in practice, you'll find that most authorities do not charge for responding to a request.
If you have a disability, and because of that you want information in a particular format, an authority can't pass on to you any extra costs it has to pay to provide it in that format.
Most information which is already published is free of charge, or available for a small fee. If there is a charge, this will be set out. If you ask for information which is not already published, in most cases you will not have to pay for it.