It's better to buy from a fellow manager then in the auction. Why spent over 20 coins to buy from Nordeus when you can buy from other manager and give him a couple of coins (sure Nordeus will also earn on this deal - about ten coins, what's very much indeed) so the coins will stay in our managers game.
I see auctions over 40 - 200 coins. And for 200 coins you can buy my whole team :-).