That's easy: 8" GSO Dobsonian. From Andrews they're around $400, somewhat more from Bintel but with expert support and service, and better accessories. Tube fits in the back seat of a small hatchback and the base in the boot.
If you
must have a refractor, AOE (
www.aoe.com.au) have decent refractors for under $500. Longer is better with these cheap ones because they will have less false colour. You will see a lot less with these than with the Dob.
Good second hand budget scopes are hard to find. Prices have been coming down rapidly in recent years, so a 3-4 year old scope would have to be sold at a 70-80% loss to the owner to compete with current new prices. And mirrors do age and need realuminising every so many years.