http://www.amazon.com/Garmin-010-10764-00-Charger-Rino-530/dp/B000FCMXSA

Looks likes it's only $25

Just use regular batteries in it until you get the charger. Much cheaper than a brand new gps receiver. Also, update the firmware.

That is an older, but nice unit. It also has the radio, which you may not use (probably not, unless you have a partner in the distance).

Later on, save up to buy something beyond an entry level gps receiver. At least get something with the sensors in it (compass and barometer) Which your current Rino 530 most likely has. That will make it easier to get directions to the cache while you are standing still. Without a compass, you need to be moving to get the gps compass to work