No, I don't think its too much. With that age, unless you give him special training he probably will fill only fill up part of his potential, but even then, 300k is pretty cheap even for a superstar. I can't say for sure unless I see his skills though, post them here once he is off the TL. Of course it won't be much use then, now will it?
But still, if he has low skills, don't get him, because as it is he has lost one season of training. If his skills are good then get him.
"Falling in love is not at all the most stupid thing that people do but gravitation cannot be held responsible for it."