I have a Garmin GPSMap 60 CSx, which was less than $300 US. They are definitely more expensive in China, but they come with the China City Navigator and modified firmware to make it work correctly (to counter the map's built-in positional offsets). The map won't work correctly when added to an existing GPS, so the only choice (currently) is to buy the Unistrong units which, as far as I know, are only available within China.
This thread will tell you all the details you want to know and more:
http://www.pda4x.com/read.php?tid=56398
The 60CSx is an excellent receiver. Satellites are acquired quickly in almost any location and batteries last for a very long time. Seems like well over 12~15 hours, but I have never tested carefully. It's officially rated at "up to 20 hours".