Selling a bus isn't just "stick a photo online and hope"; start by gathering paperwork: proof of ownership, service history, and a current roadworthy/inspection as required in your state.
Give it a proper scrub inside and out, fix obvious niggles, and take clear, well-lit photos of exterior, cabin, seats, luggage bays, and accessibility features.
Price it sensibly by comparing similar buses (age, kilometres, seating, gearbox, air-con, wheelchair lift), then write an honest description with VIN, rego, and any recent work.
List on Tradingpost and similar marketplaces, be ready for inspections and test drives on safe, private property, and keep insurance current.
For payment, stick to verified bank transfer, sight ID, and don't hand over keys until funds clear; complete transfer of registration and provide a receipt with VIN and odometer.