Authors are entitled to various discounts on purchases, and should consult the contract that they signed with the press to see their entitlements.
Authors of a monograph and editors of collections are typically entitled to a 40% discount on purchases of the monograph or collection that they authored or edited (this is normally stated in clause 17.1 of the standard contract). They are also entitled to 25% discounts on any other books published by the press (see clause 11.7 of the standard contract), though this does not apply to journals, digital, or online products.
The same entitlements apply to authors of articles published by the press (see clause 6.3 and 6.2 of the article consent-to-publish form).
If in doubt about these entitlements, please contact the press.