Upon Publisher's publication, Author shall be entitled to receive free copies of each edition: at least 25 print copies of the hardcover, 25 copies of the paperback edition, [5-10] copies of any physical audio recording, and two copies each of any ebook, electronic audio edition, and any sublicensed edition. In addition, Publisher will provide Author with a copy of a final, typeset proof of the Work in electronic (for e.g., PDF or Word) format. Author may purchase additional copies for personal use and for sales in connection with Author's speaking engagements at [half the cover price/cost plus shipping]. Author will be billed for these copies and payment shall be made prior to shipping unless Author's royalty account has sufficient excess royalties accrued over and above the advance payable to Author so that these charges can be recouped from Author's royalty account.
Many authors are able to obtain at least 25 free copies of each print format edition, two of each electronic edition, up to ten copies of any audio edition or sublicensed editions, and a final MS Word or PDF copy of that edition as well as the right to purchase additional copies at a flat 50% discount.
Publishers will typically agree to a provision similar to Section 18 in the Model Contract. In publishers' standard contracts, this clause often requires that copies purchased must be for the author's "personal/own use, and not for resale." If you anticipate situations, such as a book tour, where you will want to have copies on hand for resale, negotiate to delete "not for resale," or simply compromise by modifying the clause as follows:
…for Author's own use or for resale in connection with Author's professional activities, and not for use through standard retail or outlet channels.
Higher discounts are often available if you are willing to purchase in bulk. It is not uncommon for an author to receive a discount of up to 70% if willing to purchase over 5,000 copies in a single transaction. Note that these purchases will be non-refundable.