The Lexmark T640 series includes some of the most expandable and feature-packed laser printers we've reviewed to date. Read our review of the $699 T640 base model for details. You can add input trays to expand this printer's maximum capacity to a whopping 3,850 pages. To buy a version with networking built in, look for an n in the product name, such as the T640n. A d in the name indicates double-sided printing, and a t represents an extra paper tray. The T640dtn deluxe edition includes a duplexer, an extra paper tray, and networking for $1,449.