Your maths are pretty close, although I don't have an accurate read on the wholesale price, what you are doing is comparing that wholesale price against the wholesale price advertised on eBay, and you are finding that they almost the same.
You have to remember that eBay is a wholesale marketplace, when you are talking about video games, you are talking about competing against wholesaler who are selling direct on eBay, so they are selling there at the same or close to the same as what they will sell to you off eBay.
We see this time and and time again, if you are going to make eBay your market place, then you are going to have to source better than wholesale price, or you will stand no chance!
If you honestly believe that creating a successful online business will be easier that dealing in cars, then you are in for a seriously big surprise.
It's no easy road, and there aren't many short cuts to get you there any quicker!