Wand scanners are the least expensive but require contact with the bar code label.
The most versatile bar code scanners are laser scanners. Decoders are generally of two types, keyboard wedge or serial wedge, the name being derived from the type of computer interface being used. Serial wedge decoders are most common in mainframe terminal applications, whereas keyboard wedge interfaces are popular in the PC and Macintosh environments because they allow bar code scanning to be added to almost any application without modification to the application software. Today, many scanners have the decoder logic incorporated into a chip within the scanner, eliminating the need for a separate piece of hardware. Since components you don't have can't fail, PIPS strongly recommends this approach whenever possible.