Well, I’ve found two second hand record shops in the Brisbane CBD, located almost around the corner from each other.
The first is The Record Exchange which is located upstairs on level 1, 65 Adelaide street and has a huge range of LPs and singles. They have a private catalogue which I’ve not seen yet with a lot of rarer and collectable titles. Prices are aligned to condition, popularity and rarity.
The second place is Rocking Horse Records which is located in the Queen Street mall part of Albert street (245 Albert Street) and is a bit more orientated towards sale of dance/techno (less older records).
Edit/Update:I went into Rocking Horse records a little while ago. They have an impressive range of re-release records (vinyl) but not vintage (authentic original) records. The prices aren’t cheap (average $30 for a record). Their basement section is basically for DJs wanting to stockpile the latest trance/techno/rave music on vinyl with an impressive array of mixing boards, turntables and so forth. Couldn’t find any second hand vinyl, and I doubt it would have been cheap.
There was a basement place further up Queen street which had second hand LPs but the condition of said LPs was questionable, selection also questionable but prices were reasonable.