@Tim diymike the Asian doesn't recommend selling electronics like this guy but it is interesting to see. This man says 80% of his ebay sales/profit are from cell phones and those specific ones. Also, he tells us how much he bought them for and when he estimates to sell them. It might give us a good idea of what selling is like no matter what the item perhaps.
https://m.youtube.com/watch?v=yHqSSPVRASI