Getting quotes is the most accurate way to find out how much your move is going to cost because each move is different, but here's some examples that give you an idea of what it might cost. All of these costs assume that you pack up yourself but most moving companies will offer added services like packing or sell you boxes in addition to this.
Moving from suburb to suburb isn't as expensive as you may think. Increased competition over the past 5 years has made moving extremely competitive and more than comparable to hiring a van and moving yourself - plus not only do you get a van, you also get muscles and packing experience to go with it. Insurance is a standard part of the costs but you may pay a little more if you have specific items you want to specially insure.
Your options with interstate moves are slightly more extensive and therefore almost impossible to predict. You can ship things in a variety of ways - truck, train, occasionally boat or even plane. You also will need to factor in storage costs if necessary which can increase the price significantly. Some companies specialise in the long distance moving cheaply and you would need to organise a local removalist to collect at their storage units.
If you're deciding whether to hire a van and do it yourself or use a professional removal company, remember to factor in the insurance on the contents in transit, as well as the cost of returning the van/truck to a different rental office or driving it back.
The prices are relatively static throughout the year but the summer months are busiest. Flexibility is often the way to keep the costs of moving interstate down most.
The services that companies who do removals internationally are a lot more diverse. Many offer advice about tax, import duties and so on, as well as providing you with special boxes in the case of a smallish move. Shipping via sea-freight is your cheapest option and can take up to 90 days to reach the destination.