Here is my 2 bobs worth of advice....
Remember that when importing 'stuff' by post or air freight that there is a $A1,000 limit before you are required to pay duty and GST.
http://www.customs.gov.au/site/page.cfm?u=5653 I don't believe this generous limit applies for shipments by sea i.e. all container shipments are subject to duty and tax.
Re Shipping Costs.... if you don't like surprises on your credit card statement then get a quote from the supplier for shipping costs. For example, I once bought a couple of mufflers & pipes from the US and the shipping cost as much as the mufflers. The Bad News was it cost $1,100. The Good News was that I had 'em in 3 days :-)
If you don't like the shipping quote ask about if they have alternative shipping modes ie the USPS tends to be cheaper than private shipping companies. Also, you may not want to receive it by Express Delivery (nor did I but I learnt).... :-)
For large items such as wheels, tyres, and engine blocks, talk to an Australian Auto Shipper (see Just Cars or Unique Cars Magazine) and arrange for them to slip/ship your item into their regular container. Obviously, choose an Oz Shipper who has a delivery depot in your state capital. Your US Retail Supplier just has to ship (the lower 48 States) to the LA connection(which is relatively cheap). The Oz Shipper will tell you who in LA to send the stuff to. Be prepared to wait 6-8 weeks.... the boat will probably go via Pusan Korea.... if you know the container ID you can track it's progress on the Internet.
Finally, since I am talking about saving money, if you are buying a lot of stuff on the internet then ask your bank what charges they hit you on your overseas credit card purchases(Or every day charges for that matter). I don't usually give free plugs, but I picked up a credit card from Wizard with the following features:
No annual fee.
No fees for cash advances.
No fees for overseas purchases.
An annual percentage rate on purchases AND cash (unlike some other credit cards) of just 14.99%.â€
4.99% p.a. interest for six months from account opening on balances transferred.#
Up to 55 days interest free.‡
http://www.wizard.com.au/creditcards/task.aspx?id=580Errrr... and no bullsh.t Fly Buys or Rewards.
If you can find a better card than this then I'd be surprised. Oh re their monthly payments, I pay via BPay from my Bank Account over the Internet.