From my research results, it looks like the Garmin and Tom Tom make affordable GPS devices. It all depends on what type of GPS you are looking for and the map services that come with it.
The cheapest personal GPS tracking device is the Bushnell GPS. These GPS cost around $50. You can purchase the Bushnell GPS online from stores such as Best Buy.
On Google shopping, we found the cheapest GPS units are $50. It is the Magellan RoadMate 1424 and can be found for that price at Pricefalls.com.
The cheapest Garmin GPS is the Nuvi 205 3.5" Portable GPS. It is available at Walmart: http://www.walmart.com/ip/Garmin-nuvi-205-3.5-Portable-GPS-Black/13020913.
There are many different GPS car navigation systems on the market and some can be purchased for reasonably low prices. Research has shown that the cheapest GPS currently on the market is the TomTom ONE 130S.
The Garmin looks to be the cheapest GPS available. You might want to look at different discount stores such as wal-mart. You might be able to find a better deal.
The cheapest GPS systems are good for casual use. These are not always the most reliable and up to date systems, and can have software incompatibility issues.
Garmin Geko 201 Handheld GPS Receiver is one of the cheapest GPS devices out there for under $90.00.
Best buy is the cheapest Garmin GPS. The Garmin runs pretty cheap at an on-line e-bay site or you can bid on one this will sometimes work out real well.
The Garmin n_vi 250 3.5-Inch Portable GPS Navigator appears to be the best and cheapest GPS for your car. It is available at Amazon.com for $188.00. This GPS has great reviews.
You can look at ebay or craigslist. These websites offer the cheapest possible price for a gps.
The cheapest GPS can be found at Wal-Mart or zellers. The closest retailer would have to the shopping center 2.5km south from here on route 400, just on the left past Stubo's.
The cheapest Garmin GPS will be a refurbished or used device. Ebay.com and Amazon.com are great places to look. Also check out Newegg.com and Bestbuy.com for inexpensive new models.