Don't take it the wrong way dude. It's great to have you around, but if people have a bike to sell it'll be in the "for sale" section. Do you have any idea of what style of bike you're looking for? Personally I reckon your best bet on here at the moment would be Supercharged's FZR. Well kept from what I hear, and great price. (Seen it out and about and it looks sweet too.)
In saying that, if you have been through the quokka (as I did this week and bought my bike), there's heaps of choice, and all within your price range! Yes a couple are higher, but people can be bartered with. And the worst they can say is no.
For example:
SUZUKI GSX250 Across, 1996, 4 cyl, runs well, gd tyres, low km, 3 mths regn, black & purple $3800 ono. Wkiki. 9591-1091
SUZUKI GSX250, 1983, red & silver, gd tyres, 2 into 1 exhaust, recovered seat, gear rack, 41,000kms, clean & tidy, 6 mths lic $1300
KAWASAKI ZZR250, 1993, lic to Nov, gd cond $2200 ono. N Yunderup. 9537-8094
KAWASAKI GPX 2005, black, vgc, 6 mths regn $3800 ono. Knrs. 0407-880-911
YAMAHA Scorpio 225cc, 2007, as new cond with under 2000 kms, lic, c/w helmet, dryrider jacket $3000. Mndrh. 9534-8369
I did most of my learning on this model bike. Switched to a CB for the test. It's a nifty, zippy little bike with a great turning circle.
YAMAHA Virago 250, great cond, must sell $2000. Dblvw. 9445-3293
HONDA CBR250R, 1988, 22,000km, black & silver $3000. Inloo. 0428-350-544
KAWASAKI ZX2R, 1994, black, red visor, new front brakes, new batt, new, new chain & sprockets, excel cond $3750 ono. Vic Pk. 0429-309-842
That's only the first 6 or so pages. There's another 9 that I didn't go through again. If you need a hand with things to look for when checking bikes out, there will always be someone around who can give some good advice (chances are it's already been asked before though, so try searching for previous threads first.)
As you can see though, it's all out there waiting for you - go find your favourite!
