1. Recreational grade GPS receivers are sold at most box stores and at many sporting goods and camping stores. They are also available widely through Internet retailers. These units are the least expensive grade and are generally accurate to within +/- 25 feet (7.6 meters). These receivers run in the $100 to $600 range and are the type most often purchased by the general public.
2. Mapping grade GPS receivers are generally sold by "high end" and licensed resellers. These GPS receivers are typically less user-friendly than the recreational GPS, and they cost significantly more. Mapping grade GPS are more accurate than recreational units, commonly to within a meter (~3 feet). These receivers generally cost in the $1,000 to $3,000 range. Mapping grade GPS receivers are most often used by government agencies, researchers, and other users who require more accurate and dependable coordinate fixes than a recreational GPS can provide.
3. Survey grade GPS receivers are the most accurate and the most expensive. They are accurate to within a centimeter and can cost in the tens of thousands of dollars. These GPS receivers are most often used by professional surveyors and excel in high accuracy measurements of fixed positions. Just remember, knowing how to use a GPS (even a survey grade) does not make you a licensed surveyor!