The publishers set copyright fees, either by themselves or through their agents, and the fees will therefore differ from publication to publication.
You can check the copyright fees for journals on Explore the British Library.
Please note that the copyright fees displayed on these files are indicative only. The actual copyright fee we will charge is that which is on our internal system at the time the copy is made. This may vary slightly because of currency fluctuations and, in a few cases, may be changed by the publisher or their agents during the quarter. We will do our utmost to keep such changes to a minimum, but occasionally we may have to make changes for reasons that are outside our direct control.
A default copyright fee of £12 per item is charged on certain non-journal material, such as conference proceedings and books. A fee of £0.00 applies to all items published over 100 years ago, plus certain material for which the rights-holder has set a fee of zero.