How is it priced?
Usually erect and dismantle as one figure, plus a weekly or four-weekly hire rate. Ask for both, and ask what happens if the job overruns, because that is where the surprise lives.
Do I need a permit?
If it stands on a footpath, berm or road, yes, and councils charge for it. Many scaffolders arrange it; ask whether it is in the quote or something you organise.
Who is responsible for it once it is up?
The scaffolder inspects and tags it, and it must not be altered by anyone else. If another trade needs it changed, that is a call back to the scaffolder rather than a job for the person on site.
Is shrink wrap worth it?
For exterior painting or a reroof through winter it can save more in lost days than it costs. Ask for it quoted separately so you can decide against the weather forecast.