In the first town of Riverwood, after completing the quest to get your first companion Faendal. You can pay him to train you and then request to trade with him and repeatedly take the money back from him that you just payed to train.
Seems a little broken.

D

thanks for the tip.

Except you can only train 5 times per lvl so its a little bit more tricky and he can only train you upto a certain lvl i believe.But it is a good way of getting a head start if your that way inclined lol.