Virtually every used drone sold via ebay or Amazon, will have changed hands with no flight test possible. There is a leap of faith needed to purchase a drone sight unseen, but one would like to think that reputable sellers on ebay would choose to be truthful about the condition of any drones they sell, to avoid getting embroiled in a dispute filed with ebay or PayPal, and also to preserve their reliability ratings, if they are frequent sellers on the platform.
Speaking of which, I recently purchased a Mavic Pro on ebay, and when it finally reaches me, I'll report back here with my findings about whether or not the seller's description of the drone as being "barely used, and never crashed", was an accurate sales pitch. Keeping my fingers crossed on this one, for it is my first ever purchase of a used drone.