The unit costs of printing decline as the quantity increases, in part because set-up costs account for a high percentage of the printing job cost. Once the set-up is paid for, running the press for a longer period continues to add to the cost, but becomes cheaper per unit. With many kinds of printing jobs, the cost differential between 500 and 1,000 copies, for example, is negligible. Consequently, unless you use multiples of 8, you will have blank pages and wasted paper. In the same way that typefaces affect the look of a publication, so do the text and cover papers, the most visible and tangible part of a publication.
Papers vary widely in quality, color, texture, and cost.
Unless you have a special need for a particular kind of paper, ask your printer about paper already in stock at the print shop. Print shops order papers in bulk at reduced prices, and they are almost always lower in cost than you would get from an individualized paper order. Considering that paper costs have risen markedly in the last few years, this can represent a significant savings. You should also consider the use of recycled paper. Most printers now offer high-quality recycled papers at competitive prices.