oh, I see, you saw a player, know what his price is now if you'd buy him, and wonder how much you'd get when you have finished his training and want to sell again.
Well, I can be short on that: I bought a center for 1M8 or 1M6 a few seasons ago, trained him up 1 or more levels in all his insides, and now he's worth 1M4. ;)
What am I getting at? Well that is is prety unpredictable how much he will be worth when you are about to sell him again. I have learned my lesson, I don't buy players anymore to train and sell with profit. I've tried it, and lost money.

If you are lucky, you can win money, but to me it's lottery. I now prefer to buy players I realy need, or at least can make good use of, and improve them how I thing they will benefit my own team most, then if they need to be replaced, I'll see what I'll get for them...

I wish everyone buying players for the sole purpose of training them somewhat and making profit good luck! they'll need it. hehe.
They are not your friends; they dispise you. I am the only one you can count on. Trust me.