Check out your Uni/TAFE gym [if you go?] - they are usually the best prices.
I am a member of the UNSW gym, and it is pretty decent. Remember... never pick a gym based on running/hamster machines... You can run anywhere. Your going for the resistance/items that you dont have access too - so pick it off the free-weights section, or machines, if your inclined to use them.
Another option is to buy your own gear. I have, i've got lots of stuff, and a lot of weight.
So i have both worlds, Uni gym, plus my own stuff. I picked to uni gym due to ease of use after class
or mid/between.
Define what you want/need. Find a gym that provides it.
Typically... the bigger the brand of gym, the worse they are.