This is one of the "problems" with an auction site.
You cannot force all sellers to be good sellers, list 7 days with 10 auto runs, list at competitive prices, make sure they have profile, promote on social media, make sure they don't use all caps etc etc.
You are dealing with thousands of individual people.
As regards wild prices you only have to check a few products on Google Shopping and there are often HUGE variations on sites other than ebid.