There's websites to compare prices for everything these days. We've got booko, staticice, boozle, shopbot, and I'm sure a lot of others.
Do you know of a website to find the cheapest vinyl records?
I've been using a combination of Discogs and eBay but I'm interested in something that's based in Australia.
https://www.discogs.com/
Ah sorry didn't read you mentioned it already. It depends what you're collecting as well. If it's a particular artist, there is usually a forum dedicated to vinyls for that band, unless they are lesser known. Heaps of forums have buy and sells and you don't get ripped off as bad as ebay!