Skill trainer

A Skill Trainer is an NPC who teaches new skills. In addition to whatever skills a trainer normally teaches, each skill trainer teaches all non-elite skills you have unlocked on your account (since the March 10th, 2006 update).

Price
Learning a skill from a skill trainer costs one skill point and some gold. The price in gold increases per skill to a maximum of 1 platinum (1000 gold) per skill after buying 20 skills.

Skill Trainer List
For a list of all skill trainers and a list of the skills they offer, see:

Skill Trainer List