The cost to equip an aircraft with a GPS TSO C129A receiver varies depending on the type of the receiver, the degree of difficulty of the installation, the sophistication of the aircraft and existing avionics, and the level of services desired. Also, the cost of equipping will vary depending on whether GPS is used as a stand-alone system or as part of a Flight Management System (FMS). Most dealers provide a package price when they sell a receiver. This package includes installation and airworthiness inspection, as well as the actual equipment. These packages can range anywhere from approximately $3,000 (US) for a basic general aviation IFR GPS receiver installation/certification, to $10,000 (US) for a more sophisticated GPS receiver installation/certification on a commercial aircraft. When comparing prices of GPS avionics versus existing ground-based avionics, one must consider that one GPS receiver will eventually replace all avionics associated with these other ground navigation aids (VOR/DME, NDB, and Category I ILS).