Yes, GPS can be VERY usefull for hunters and I've been using the system since 1995.
The thing is though, that you must learn how to use them properly before venturing into the unknown!
Your first GPS should be a simple unit without too many menu options which can create confusion.
Once you've mastered the basics you could then upgrade to a more complex unit if you feel the need.
A Garmin eTrex or Geco would be a good starting unit.
The Geco is under Aus$200 I think.