The classic Auctioneer auction-house addon for 1.12 (vanilla) clients, bundled with the two helper addons it needs and patched to load on OctoWoW. Current release: v1.9.3.
https://github.com/Ouba321/Auctioneer-OctoWoW
Big thank you to Ezrul and Teotta for helping me test the addons functionality ...