I would add to Gully's very sensible post that the 3 main drivers to a trainee value are: potential, total skill points and age (18yo are worth more than 19yo because they can reach their potential faster and at a younger age). 45+ skill points and low potential (starter, star) are almost always worth something and the same goes for high potential lower skill points trainees. Height also plays a role combined with how the skill points are distributed but that's probably less of a factor at such a young age. A 18yo trainee with close to 60 skill points and MVP or better potential are worth (and will sell for) a LOT of money.