If you are purchasing a 2nd hand vehicle then it’s useful to get a REVS Check or PPSR Check to ensure that the vehicle you purchase doesn’t currently have any money owing against it, or hasn’t been previously written off and repaired or stolen. It’s worth spending the money for the peace of mind it offers. If you are looking for a REVS Check for a VIN number or Chassis number, give VINNER REVS Check a try, reports are only $9.90 which is far cheaper than the other site listed. It's completely optimised for mobile and supports PayPal along with credit card payments (including Amex) via a secure Australia payment gateway. For those older cars that are pre-1989 you can request a chassis reports here, and if you are planning on buying a boat you can also perform a HIN check if needed. VIN reports also cover all other vehicles (including trailers, caravans, 4x4, trucks etc) for any other types of vehicles you are considering for your trip.
[disclaimer: I'm the owner/developer of the site so please support the small guys, and happy to answer any VIN related questions.]