Ever since Harvey Norman, that bastion of free enterprise, convinced the government that GST must be collected on everything imported it's become, as the Yanks say, a crapshoot! The overseas company that sells you something is supposed to charge and collect the GST on behalf of the Australian Government (
) but I haven't heard of any US company doing that. Aliexpress collects it, so does ebay and Paypal, so if you use Paypal you will be charged IF the seller includes it on the invoice. In general, however, US companies just say that local taxes etc are your problem, they don't want to know about it.
Once upon a time items over $1000 were held by customs and you were notified of any outstanding taxes, but I'm guessing if that's still the case it will be hit or miss whether your goods get stopped due to the huge amount of parcels now being handled. Aust Post already said they won't handle collection of GST/taxes because they don't have the staff to do it.
If your parcel is relatively small, regardless of value, there's every chance that it will go through without being checked.
As for using a Customs Broker, unless your goods are large/heavy/bulky/very expensive then I can't see the point. I investigated that path once, when I was looking at importing an industrial sewing machine, and by the time I went through every step (with an additional cost at every turn!) there was nothing to be saved. I bought it here for pretty much the same as it was going to cost me to import it - and with a lot less hassle!!
